As King Charles turns 76, it will be a bittersweet occasion as he contemplates how much has changed within his close family – with some bonds made stronger than ever by a difficult year, while his relationship with his younger son Harry remains, at best, distant.

Before Charles was King he spent 64 years as the longest-serving heir apparent and Prince of Wales in history.

During that time the workaholic royal eagerly planned to make an impact on a wide array of causes close to his heart when his time to rule came – from the environment to disadvantaged young people.

But despite the long wait to serve his country, only 18 months into his reign Charles was diagnosed with cancer in February and began the gruelling process of treatment which limited him at times to an almost Covid-like ‘bubble’.

However the monarch has been able to rely on his daughter-in-law Kate, who announced her own cancer diagnosis in March, and his wife Queen Camilla for support.

He already viewed the Princess of Wales as the ‘daughter he never had’ but they have bonded even more deeply over their battle with the disease.

Meanwhile, he’s relied  on Queen Camilla to step up her public engagements without him – which she’d done with aplomb, despite the fact she’s not a ‘natural’ in the role, according to Princess Anne.

But other family relationships remain fraught, with his disillusioned son Prince Harry and his wife Meghan Markle continuing to live in California.

Here, on the day King Charles turns 76, MailOnline goes inside his relationship with the two pillars who have been supporting him through a brutal year – Princess Kate and Queen Camilla.

The monarch has been able to rely on his daughter-in-law Princess Kate, who announced her own cancer diagnosis in March, for support. Pictured together at the premiere of No Time To Die in September 2021

King Charles III, Kate and Princess Charlotte stand on the balcony at Buckingham Palace to watch the RAF flypast during Trooping the Colour in 2024

King Charles III (wearing a kilt made from the King Charles III tartan) and Queen Camilla attend The Braemar Highland Games in September 2024

Meghan Markle and Prince Harry pictured on their quasi royal tour of Bogota in September 2024

Charles’ growing bond with Catherine as they battle cancer together

The monarch shares a close bond with his ‘beloved daughter-in-law’ – and their shared health struggles have only ‘cemented’ that special relationship, one well-placed source told The Telegraph recently.

So much so, Kate appeared to include a special tribute to the King in her moving three-minute video, which was released in September and showed the Princess and Prince William celebrating her recovery alongside their three children.

In recent times, Charles and Kate’s close bond has regularly been proven, including at Trooping the Colour this summer, when the Princess made her triumphant return to public life by joining the Royal Family for the King’s Birthday Parade in London.

In a departure from last year, when King Charles stood next to his heir Prince William, this time around, he stood next to Kate.

This was significant, according to body language expert Judi James, as she explained to FEMAIL at the time: ‘Charles made Kate his centre of attention to signal both how much she is cherished and how grateful he was at her attendance.’

It has long been thought that the King and the Princess are close thanks to their shared interests in the arts, among other reasons.

Judi told FEMAIL: ‘Charles has always had an increasingly special relationship with Kate, who he has grown to trust and delight in.

‘Here though, that relationship was highlighted to illustrate how those bonds have only deepened and enriched by their bonds of empathy created by their illnesses.’

Recently, a royal expert claimed that Charles has ‘always had a great respect for Kate’ and would ‘compare notes’ with her on their hospital’s food during their ‘affectionate’ meetings about their respective cancer treatments.

The pair both received treatment at the London Clinic in Harley Street earlier this year.

Appearing in the Channel 5 documentary Kate: A Queen for the Future, the Daily Mail’s editor-at-large Richard Kay discussed Charles and Kate’s meetings during their time as patients in the hospital.

Richard explained: ‘The King actually made a point of going to see Kate and there’s this rather touching story of [Charles] in his dressing gown padding down to his daughter-in-law’s floor.

‘They compared notes about the rather good hospital food, how their treatment was going. It was a moment of great affection.’

The London Clinic’s head chef Paul O’Brien leads a team which provides customised meals for patients, sourcing ingredients from Home Counties farms.

The then-Duchess of Cambridge and Prince of Wales have been snapped sharing a chuckle on a number of occasions, including during this event at the Defence Medical Rehabilitation Centre Stanford Hall in Loughborough in February 2020

Images showing the closeness, such as this photo from the service of thanksgiving for the Queen at St Paul’s cathedral on June 2022 make it clear why Charles has several times said that the family is ‘lucky’ to have Kate

Kate’s willingness to get stuck into any task means she has become a well-liked member of The Firm – with family members as well as the public! (Pictured trying to iron artwork onto silk during a visit to the Dulwich Picture Gallery in March 2012)

Elsewhere in the documentary, The Telegraph’s royal correspondent India McTaggart said King Charles has always valued the Princess of Wales.

She explained: ‘Charles always had a lot of respect for Catherine and he said that in the wedding toast that he made. He said they were very lucky to have her and it remains true to this day.’

Later in the documentary, royal expert Robert Jobson said that Kate Middleton plays a crucial role in King Charles’ relationship with three grandchildren.

The expert said: ‘Catherine is very important in the relationship between Charlotte, George and Louis and the King.

‘When William and the King aren’t necessarily on the best of terms, as sometimes fathers and sons are, it’s always Catherine who makes sure that the King, if he wants to see his grandchildren, sees his grandchildren.’

The King reportedly thinks Kate is doing a ‘wonderful’ job bringing up George, Charlotte and Louis, and gets to spend more time with his son’s family now they live just a few minutes drive away from Windsor Castle.

Kate is known to have a warm relationship with her father-in-law and has reportedly helped smooth the sometimes fractious relationship between the King and his son, William.

King Charles and Kate have also shown several public signs of their close relationship over the past few years.

For instance, the Princess of Wales lovingly called her father-in-law by his family nickname of ‘grandpa’ when she greeted him at a G7 reception in 2021.

Meanwhile, in April 2021, the then Duchess of Cambridge shared a kiss on the cheek with her grief-stricken father-in-law as they left Prince Philip’s funeral.

Kate consoled Charles as the pair walked out of St George’s Chapel following the emotional service in memory of the Duke of Edinburgh.

Photographs show Kate comforting the then Prince of Wales over the loss of his father by putting her hand on his shoulder. She then kissed him on the cheek as they set off from the entrance of the chapel.

Elsewhere, when greeting one another at engagements, Kate and the King will often share a friendly embrace and pecks on the cheeks.

At William and Kate’s wedding, Charles movingly described his son’s new wife as the daughter he had never had during the speech and admitted: ‘We are lucky to have her.’

In a touching speech, the clearly emotional prince paid tribute to his new daughter-in-law – but still found time to crack jokes about his eldest son and his famously thinning hairline.

Queen Camilla steps up for her husband and finally secures her position as respected consort

Although she was once considered to be one of the most unpopular women in Britain, this year has seen Queen Camilla’s warmth, humour and strong sense of duty largely win over any remaining critics.

Amid the King’s cancer battle, Her Majesty, who turned 77 in July, kept the Royal Family united and stepped up her duties, standing in for her husband as he underwent treatment.

Such is her warmth and unquestionable dedication to her duties, she’s been nicknamed ‘the nation’s grandmother’, winning praise from well-wishers and members of the Firm alike for her steadfast presence amid a turbulent time.

She has shown her commitment to her role as the King’s consort many times throughout the year, with her even arriving in Guernsey in July sporting a bandaged ankle after suffering a ‘slight sprain’.

King Charles III and Queen Camilla depart The London Clinic after Charles underwent a procedure for an enlarged prostate. It would be announced shortly after that he had cancer

King Charles III and Queen Camilla greet fans at Sydney Opera House on October 22, 2024 during their Australia tour

King Charles III and Queen Camilla attend day four of Royal Ascot in June 2024

But she refused to let the injury stop her from joining Charles on the second day of their two-day tour of the Channel Islands.

It wasn’t the first time the Queen’s determination to play her part has been on full display – with this year completing Camilla’s remarkable transformation from understudy to centre-stage star.

No one in her orbit – let alone the lady herself – dreamed that she would one day be crowned at her husband’s side (with the blessing and approval of Queen Elizabeth, no less), let alone stand in for His Majesty at prestigious events.

But these past months have seen her prove her place in the Royal Family, after she found herself, to all intents and purposes, the King’s front of house.

Buckingham Palace announced in February that the monarch had been diagnosed with cancer and would be taking a break from his public-facing duties as he began treatment.

Straight away, Camilla, who has been credited with keeping the ‘royal show on the road’, was on duty almost every day, combining back-to-back engagements with supporting her husband.

She led the Firm at the service of thanksgiving for the late King Constantine of Greece in February, stood in for the King at the annual Royal Maundy service in March and also met the first lady of Ukraine, Olena Zelenska, at Clarence House.

King Charles III and Queen Camilla depart the Macmillan Cancer Centre on April 30 after their first engagement following Charles’ cancer diagnosis

She also undertook a solo two-day visit to Belfast in Northern Ireland in March for a series of engagements that had been arranged before the King was diagnosed with cancer.

It was previously reported that Camilla was ‘proud’ to take on more duties amid Charles and the Princess of Wales receiving their treatment for cancer.

The Queen is ‘resilient’ and will do anything that is asked of her to help the Royal Family, aides reportedly told The Telegraph – despite Her Majesty in past describing royal duties as being ‘tiring’ to carry out.

‘Very tiring,’ she admitted during an audience with the Sultan of Brunei’s wife, Queen Saleha, six years ago. ‘Every day, we’re non-stop. It’s more tiring as you get older. I keep trying to tell everybody that I’m not as young as I used to be, and have to slow down.’

But she has been the ‘steady hand on the tiller’ amid the King’s cancer diagnosis, a former royal butler said.

Speaking to GB News earlier in the year, Paul Burrell remarked that the monarch’s wife is the ‘guiding force’ for the family, as well as being the one behind Charles’s openness regarding his health.

‘I think she is the stabiliser,’ he told the outlet. ‘I think she has that touch. I think she’s able to reach people in a way the King can’t and I think she’s taught him a lot in the last few years about monarchy and how to be King.

King Charles III and Queen Camilla watch The King’s Parade under torrential rain during a visit to Jersey on July 15, 2024

Queen Camilla and King Charles III attend the Order Of The Garter Service at Windsor Castle on June 17, 2024

‘Isn’t that odd really, that she should come up through the ranks and be so supportive and such a stabilising influence in our modern-day Royal Family.’

Meanwhile, it’s not the first time Camilla has been praised for her ability to step up to the task when times get tough.

Her straight-talking sister-in-law Princess Anne said Camilla is ‘not a natural’ at the role – but she ‘does it really well’ and ‘provides that change of speed and tone, that’s equally important’.

It’s a stark contrast to how Camilla was viewed in the early years of her and Charles’s relationship – with even the late Queen initially ‘wanting nothing to do with her’.

Just 12 months after the crash in Paris in which Princess Diana was killed, Charles went to see his mother, looking for approval and support for his relationship with Camilla, then Mrs Parker Bowles.

It was not a happy meeting. As a highly placed royal confidante told The Daily Mail then: ‘The Queen told her son she never wanted to talk about that wicked woman, and wanted nothing to do with her.’

However, the late monarch personally endorsed ‘Queen Camilla’ in the end, accepting Charles’s former mistress as a respected member of the Firm.

Royal expert Joe Little, of Majesty Magazine, previously remarked: ‘I think only now are people appreciating the true worth of Queen Camilla.’

Meanwhile, one royal retainer, who has witnessed many of the family’s twists and turns over the years, told The Daily Mail’s Royal Editor Rebecca English earlier this year that they are genuinely glad to see Camilla’s diligence and sense of duty recognised at long last.

‘She’s been an absolute trooper, really she has,’ they said. ‘She just gets up and goes out there, doing exactly what’s asked of her with a smile on her face.

‘I always think you see the best of people at the worst of times, and I really hope people realise how true that is here.’

Another member of their circle said: ‘She’s absolutely out there leading from the front.’

Dame Joanna Lumley couldn’t have agreed more; the national treasure was one of many queuing up to sing Her Majesty’s praises at a Clarence House reception to mark three years of Camilla’s phenomenally successful book club, The Queen’s Reading Room, in March.

‘They [the Royal Family] are all extremely dutiful. It’s like the theatre – if someone is ill, someone steps into their place, the understudy keeps the show going,’ she said.

‘She is the epitome of professionalism and public service. Everyone thinks she should be blubbing in a corner, but this is not what these people are made of. And it’s something we should aspire to.

Queen Camilla gets a hug from Rebecca Tessinari, 3, during a visit to the newly opened Meadows Community Centre in Cambridge on February 2, 2024

‘If you sit alone feeling sorry for yourself you will feel sad and tragic. But if you get up and do something with a smile, then you feel better. ‘

Best-selling thriller writer, Harlan Coben, agreed. ‘She’s a keeper, as we say in America,’ he enthused.

Meanwhile, the Queen further won over the hearts of the nation this year with her emotional display at commemorative events for the 80th anniversary of D-Day.

Camilla did not shy away from showing emotion as she joined Charles (who has returned to public duties), the Prince of Wales, UK politicians and veterans at major events in Portsmouth and Ver-sur-Mer in June.

The occasion was inevitably sombre, as shown by Her Majesty shedding a tear when listening to a veteran recount the horror of losing his best friend on the beaches in Normandy 80 years ago.

But amid the heavy and deeply moving testimonials, Camilla also shared heartfelt moments with multiple former soldiers, who smiled and enjoyed light conversation with the Queen.

So, from her displays of warmth and emotion, to her loyalty to her husband and sense of duty, Camilla’s year as the Royal Family’s leading lady has no doubt secured her position as a respected consort and comforting ‘grandmother figure’ to the nation.

Prince Harry and Meghan Markle continue to live out in California as their royal insignificance grows

In contrast to his sister-in-law and his stepmother, Prince Harry has remained firmly on the outside of his father’s support network.

Alongside his wife Meghan Markle, the pair have continued to live in increasingly growing insignificance in the celebrity enclave of Montecito in California.

After hearing about his father’s shock cancer diagnosis in February he flew to London for a brief 45-minute meeting with Charles.

The King had called him personally to tell him the devastating news and the Duke immediately jumped on a plane so he could get to the UK as soon as possible.

It was hoped seemingly in vain that Harry’s return to Britain would help heal wounds with King Charles and be a chance to reach out to his William amid years of strained relations.

In contrast to his sister-in-law and his stepmother, Prince Harry and his wife Meghan have remained firmly on the outside of his father’s support network. Pictured together in 2018

Prince Harry and Meghan Markle video message at the inaugural Global Ministerial Conference on Violence Against Children in Colombia

But the Duke did not see his brother William or sister-in-law Kate, who at that time was recovering from her abdominal surgery and on extended leave.

Although very short, it was their first formal meeting in person since the late Queen Elizabeth II’s funeral in September 2022.

The prince did attend Charles’s coronation at Westminster Abbey in May last year but was not seen interacting with the newly-crowned King and Queen.

The Duke and Duchess of Sussex abandoned royal duties in early 2020 to live in the US.

Harry has been critical of his family in TV interviews and his book, Spare, which was published last year.

The bombshell book featured staggering insights into the prince’s relationship with his father and brother.

Harry has barely spoken with his father since the death of Queen Elizabeth.

In Spare, Harry had revealed that Charles had urged his warring sons: ‘Please boys, don’t make my final years a misery.’

But it seems despite his cancer, Charles’ sons have been unable to make amends, with them having reportedly not haven spoken in several years.

Meanwhile it is the women in Charles’ life, Princess Kate and Queen Camilla, who have stepped up to support him in his time of need.