Their love lives became perhaps the most famous royal love triangle in history, with as many dramatic twists and turns as any best-selling romance novel.

While the public was only made aware of Charles and Camilla’s affair and of the then-Prince and Princess of Wales‘ marriage woes in the early 90s, within royal social circles the drama had been playing out for years.

Writing in his book about King Charles III’s life – titled Rebel King: The Making of a Monarch – author Tom Bower revealed a particularly testy encounter between the three that played out at a birthday party in 1989.

The altercation occurred when Diana arrived unexpectedly at a party for Annabel Goldsmith in her home in southwest London, where Camilla and her then-husband Andrew Parker Bowles were also guests.

Bower wrote: ‘Diana arrived unexpectedly at a birthday party at Annabel Goldsmith’s house in Ham, near Richmond.

‘Charles was with Diana, while both the Parker Bowleses were already there. As the room fell suddenly silent, Diana challenged Camilla to leave Charles alone.

In response Camilla ‘controlled her fury’ and told the princess that her behaviour was ‘unacceptable in a private house’.

Bower said: ‘The princess, she said was poorly placed to complain. While Camilla confined herself to a single, conventional relationship, Diana, she had been told by friends, was “working her way through the life guards”.’

Diana in 1992 around the time of her separation from Charles. While the public was only made aware of Charles and Camilla’s affair the then-Prince and Princess of Wales’ marriage woes in the early 90s. Within the royal social circles the drama had been playing out for years

Camilla in 1989, writing in his book about King Charles III life – titled Rebel King – author Tom Bower revealed a particularly testy encounter between the Princess of Wales and Camilla that played out at a birthday party that year

Diana and Charles at a Downing Street event in 1989. The Princess of Wales unexpectedly joined Charles for a birthday party in south west London

‘Camilla’s intimates blamed the bruising encounter on Diana for creating “such a public scene”. Others accused Camilla of b***hiness.’

In 1989, Charles and Camilla had been spending more and more time together.

They holidayed in Turkey together along with Camilla’s husband. The future Queen consort was pictured wearing a bracelet that was emblazoned with the initials G and F – a reference to Charles and Camilla’s pet names for each other, Gladys and Fred.

Diana and Charles separated in 1992 the same year the princess’ authorised biography – Diana: Her True Story – was published. It contained the first public mention of the affair between Charles and Camilla.

It would be another year before the press received undeniable proof of the affair following the ‘tampongate’ scandal, which saw transcripts of an intimate phone conversation between the couple from four years earlier made public.

Bower claims that from then on ‘the battle of the Waleses had aroused global fascination’, helped in part by the role each party played in the drama.

He said: ‘Britain was divided about where the guilt lay. The majority, especially women, blamed Charles. They believed the version written by Richard Kay, the Daily Mail journalist and Diana’s confidant: “I knew a girl of utter simplicity, even naivety – frightened, uncertain and delightful company”.’

Diana did not come off scot-free, however. Bower wrote: ‘Visitors to Balmoral described a very different figure. Their accounts portrayed a manipulative woman intent on wrecking relationships, especially her own with Charles and with his mother.’

Diana and Camilla pictured together in 1980. The omnipresent Camilla would continue to haunt Diana’s relationship with Charles

The then-Prince Charles in 1989 during a visit to Indonesia

The altercation occurred when Diana arrived unexpectedly at a party for Annabel Goldsmith (pictured)

In 1989, Charles and Camilla had been spending more and more time together. They holidayed in Turkey together along with Camilla’s husband (pictured)

And, of course, Camilla faced her own criticism for her part in the love triangle. Bower added: ‘Blame also fell on Camilla. Many times, her critics believed, she could have stood back to allow Charles and Diana to reconcile. Instead, she coldly pushed her rival aside.’

Camilla met her first husband – Guards Officer Andrew Parker Bowles – but before they married the couple found themselves in one of the most bizarre royal love triangles.

How the Queen and Prince Philip tried to change Charles and Diana’s ‘sorry story’

Camilla and Andrew broke up in 1970 and a year later Charles entered the picture. He and Camilla immediately hit it off and a young romance began to blossom.

However, Queen Elizabeth II and the rest of the family were not so enthused about Charles’ newfound love, in part due to Camilla’s on-again-off-again relationship with Andrew, which they feared could cause issues for the heir to the throne.

The Queen Mother organised a secret meeting with both the Shand and Parker Bowles families, where a wedding date was swiftly agreed. The couple married in 1973.

Charles and Camilla remained close friends throughout the rest of the 1970s and they were frequently spotted at polo matches together. They then rekindled their relationship in 1980 with Andrew – who had multiple affairs – reportedly supportive of the relationship.

By 1981 Charles was married to Princess Diana. But it was not a fairytale marriage, with the Princess very aware of his continued affections for his former girlfriend.

Camilla wearing a bracelet (circled) that was emblazoned with the initials G and F – a reference to Charles and Camilla’s pet names for each other, Gladys and Fred

Charles and Diana in Hong Kong in November 1989

Prince William, Diana, Princess of Wales, Prince Harry and Prince Charles, Prince of Wales, attend the wedding of the Duke of Hussey’s daughter in May 1989

The omnipresent Camilla would continue to haunt Diana’s relationship with Charles and the Princess of Wales would go on to declare ‘there were three of us in this marriage’ in a notorious BBC interview with Martin Bashir in 1995.

By 1986, Charles and Camilla’s affair was in full swing once again and Diana had embarked on her own relationship, with former army major James Hewitt

Inside Queen Camilla’s remarkable royal journey from from the shame of ‘tampongate’ to the throne

Once their relationship became public knowledge, Camilla faced intense media scrutiny because she was seen as the usurper of the much-beloved Princess Diana.

Journalist Tina Brown wrote: ‘And the press went after her with such viciousness. I mean, the really appalling sexist comments about Camilla – I mean, they used to call her, you know, old bag, old trout.’

She added that Camilla would sign her letters to Charles ‘your devoted old bag’, as she had been labelled as such so often.

Once Camilla and Andrew had divorced in 1995 – and with the finalisation of  Charles and Diana’s own divorce a year later – the couple were free to start dating privately, with Charles hosting a lavish party for Camilla’s 50th at Highgrove.

The tragic death of Princess Diana in August 1997 and the outpouring of grief from the public that followed meant Charles had to pause his efforts to rehabilitate her image.

Charles then resumed a large-scale PR campaign with Mark Bolland at the helm.

Charles and Camilla on their first public outing together in 1998

During the spin doctor’s reign in the late 1990s and early 2000s he performed something of a miracle, taking Charles’ popularity rating from 20 per cent after Diana’s death to 75 per cent.

The sad truth behind Prince Charles and Princess Diana’s wedding and her health ordeal

Bolland also orchestrated the media coverage of the prince’s first photographed public appearance with Camilla at the Ritz Hotel in January 1999 – dubbed ‘Operation Ritz’.

But Charles also had to get the Royal Family on his side.

This started with Prince Harry and Prince William, who met Camilla for the first time in 1998 at Highgrove.

With the late Queen’s approval they married in 2005 but it was far from a conventional affair.

The day was broken up into two sections – with Charles and Camilla taking part in a civil ceremony at Windsor’s Guildhall, where they were legally married, before they travelled to St George’s Chapel for their blessing from the Archbishop of Canterbury.

Camilla also eschewed the Princess of Wales title out of respect for her husband’s late former wife Diana and was known by the rather less grand title of the Duchess of Cornwall instead.

During the 1990s Charles and Camilla embarked on an ambitious PR campaign to rehabilitate Camilla’s public image

One final hurdle Camilla faced was what her title would be once Charles became King.

Palace guidance said she would only ever be known as ‘Princess Consort’ – until Queen Elizabeth II ended years of uncertainty over the issue by assuring Camilla’s future status in an historic Platinum Jubilee statement.

In her surprise announcement in February 2022, Her late Majesty declared it was her ‘sincere wish’ for her daughter-in-law to be fully acknowledged upon Charles becoming King.

Since Charles became King, following the death of his mother on September 8 2022, the now Queen Camilla is one of the most prominent members of the Royal Family – and has become an integral and accepted part of it.