His Majesty, King Charles III, will officially be crowned king on Coronation day Saturday, with thousands of spectators in attendance at Westminster Abbey and millions more tuning in around the world to witness the first coronation in more than 70 years.

In addition to the king's crowning, the coronation marks another historic day for the royal family as Queen Consort Camilla will receive a title change and become a queen herself – a move which breaks one of the final wishes from his late mother, Queen Elizabeth II. 

Charles' decision to follow his own rules as the new sovereign reflects a changing of the guards for the royals decades after Camilla became known as the "mistress who very publicly broke up the king's first marriage" to Princess Diana.

Christopher Andersen, author of "The King: The Life of Charles III," exclusively told Fox News Digital that Camilla has "worked hard to prove herself worthy of the title" following a rocky start to their romantic relationship. 

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King Charles wears blue to match Queen Consort Camilla on Easter Sunday

King Charles and Queen Consort Camillas relationship dates back decades. (Getty Images)

Despite being married for 18 years, Camilla and Charles' love story began decades ago and the couple has always had a penchant for following their own hearts. 

"Charles and Camilla first met at a polo match in 1970, when she approached him and said of his horse, 'That's a fine animal, Sir.'  Later, she was formally introduced to Charles at a party by the Chilean woman he allegedly lost his virginity to, Lucia Santa Cruz," Andersen said. 

"Camilla's first words to Charles that evening were ‘My great-grandmother and your great-great-grandfather were lovers. So how about it?’ Camilla's great-grandmother, Alice Keppel, was Edward VII's mistress."   

Camilla (formerly Camilla Shand) was an "extremely wealthy aristocrat" and the granddaughter of a baron. While Charles, one of Britain's most eligible bachelors, was deployed overseas in the early '70s, Household Cavalry officer Andrew Parker Bowles proposed to Camilla, and they married on July 4, 1973.

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Charles, Andrew and Camilla traveled in the same social circles, and were so friendly that the future king became the godfather to Camilla and Andrew's son, Tom. They also have a daughter, Laura.

Prince Charles wears white shirt and slacks while speaking with Camilla at polo match

Prince Charles and Camilla Parker-Bowles chatted at a polo match in 1972.  (Serge Lemoine)

Prince Charles in a hunter green jacket and a white shirt walking outside with Camilla in a dark green jacket

Charles And Camilla Parker-Bowles stayed friendly even after she married Andrew Parker-Bowles. (Tim Graham)

Princess Diana wears colorful sweater and khaki slacks in Scotland with Prince Charles

Diana Spencer was 20 years old when Prince Charles, 32, proposed in 1981. (Central Press/Hulton Archive)

Princess Diana in a bridal gown having her hand kissed by her groom Prince Charles

The Prince and Princess of Wales married on July 29, 1981. Diana wore a wedding dress by David and Elizabeth Emmanuel and the Spencer family tiara.  (Terry Fincer)

When Charles first met Diana Spencer in the late '70s, he was dating her sister, Sarah. By 1981, Charles and Diana announced their engagement which was followed shortly after with the royal wedding on July 29 in which Camilla attended. 

Princess Diana gave birth to Prince William in 1982 and Prince Harry in 1984. Two years later, reports began surfacing that Charles and Camilla rekindled their romance while each were still married and raising families.

By 1993, "Camillagate" hit the palace. An intimate phone call between Charles and Camilla recorded in 1989 was leaked, causing a massive royal scandal. Camilla filed for divorce from Andrew in January 1995.

In 1994, Charles was asked during a TV special if he had been "faithful and honorable" to Diana. He replied, "Yes, yes … until it became irretrievably broken down, us both having tried." Then in 1995, Diana spoke about Camilla’s relationship with Charles on BBC’s "Panorama," famously saying, "There were three of us in this marriage, so it was a bit crowded."

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Princess Diana and Charles divorced in 1996.

Prince Charles and Diana, Princess of Wales with their sons William and Harry

The Prince and Princess of Wales had two children together, Prince William and Prince Harry. (Jayne Fincher/Princess Diana Archive)

Prince Charles and Princess Diana

Charles claimed in his own 1994 biography that he was forced into the marriage with Princess Diana (seen in 1991) by his late father, Prince Philip. (Jayne Fincher/Princess Diana Archive)

"Charles will be the first divorced man ever to be crowned king, and Camilla will be the first divorced woman ever to be crowned queen," Andersen said. 

It took years for many in Britain to forgive Charles, whose admitted infidelity and long-time links to Camilla torpedoed his marriage to Princess Diana, known as "the People’s Princess." 

The glamorous young mother of Princes William and Prince Harry died in a Paris car crash in 1997, five years after her messy, public split from Charles. She was 36.

In 1999, Camilla and Charles made their first public appearance together. Then in 2005, the couple said "I do" in a private ceremony.

Prince Charles and Camilla leave Ritz Carlton hotel

Charles and Camilla first appeared as a couple while leaving the Ritz in 1999, more than three years after his divorce from Princess Diana. (Getty Images)

Prince Charles and Duchess of Cromwall marry in April 2005

Charles and Camilla were married in 2005 at Windsor Castle. (Tim Graham Photo Library)

"The King is the first head of the Church of England not to be allowed to marry in the Church of England – Charles and Camilla were married in a civil ceremony," Andersen said. "And not even the prayer service that followed at Windsor was easy for them. The Archbishop of Canterbury at the time made them both get down on their knees and beg to be forgiven for their ‘manifold sins and wickedness.’ But Charles was undeterred, and I don't think ever allowed himself to think that he couldn't make Camilla his queen."

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Camilla has worked tirelessly to win public approval after being caught in the middle of a royal affair. She supports a wide range of charities, including victims of domestic abuse, literacy programs, and animal welfare agencies.

"There's no question that Camilla has worked hard to prove herself worthy of the title. But as recently as early last year her standing in the polls was abysmal, with only one in ten Britons agreeing that she should become Queen," Andersen said. "Camilla obviously experienced a surge in popularity after Queen Elizabeth endorsed her as Queen Consort. Still, only about half the British public came around after the late Queen's thumbs-up, and even then only if Camilla was called Queen ‘Consort.’  

King Charles and Camilla, Queen Consort smiing on their wedding day alongside their children

The Prince of Wales and his new bride Camilla, Duchess of Cornwall, with their children (L-R) Prince Harry, Prince William, Laura Parker Bowles and Tom Parker Bowles, in the White Drawing Room at Windsor Castle.  (Anwar Hussein Collection)

Queen Elizabeth appears on final day of Platinum Jubilee

Camilla, Charles, Queen Elizabeth II, Prince George, Prince William, Princess Charlotte, Prince  and Princess Catherine celebrated the Platinum Jubilee last year. (Chris Jackson - WPA Pool)

Camilla with Queen Elizabeth II

Camilla and the Queen worked on their relationship despite Camilla's initial presence causing turmoil in the royal family. ( Chris Jackson)

"Recently, when the Palace made it clear that the consort part would be dropped and she would simply be called Queen Camilla, her popularity dipped again." 

Seven months before she died, Queen Elizabeth released a message thanking the public and her family for their support ahead of the 70th anniversary of her accession to the throne. 

In the note, she specified, "And when, in fullness of time, my son Charles becomes King, I know you will give him and his wife Camilla the same support that you have given me; and it is my sincere wish that, when that time comes, Camilla will be known as Queen Consort as she continues her own loyal service."

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Andersen added, "The elephant in the room is Diana. She was such a transformative figure, a force of nature, and so beloved by people around the globe – it's just hard to imagine Camilla ever clearing that hurdle. No sooner does the public start to warm up to Camilla than Harry writes a book portraying her as a schemer and a villain, and people are once again reminded of the role she had in destroying the marriage of William's and Harry's parents. Charles now has what Diana called ‘The Top Job,’ but among women in the realm, Camilla is also top of the heap – and she didn't get there by accident.         

While Camilla "knows her way around the palace," Andersen insisted "senior royals never embraced her." 

King Charles laughing with wife Camilla

Camilla and Charles "get a kick out of each other." (Rob Jefferies)

King Charles III and queen consort camilla wear blue ensembles for official portrait

King Charles III's coronation day will also include Queen Consort Camilla — as she becomes Queen Camilla.  (Hugo Burnand)

He added, "Because of all the trouble Camilla caused for the royal family and the monarchy by pursuing her extramarital affair with Charles, Queen Elizabeth referred to Camilla for years as ‘that wicked woman.’  At the moment, her biggest ally is really the only one she needs and the only one who counts: The King."  

Just as much as Camilla needs Charles, he has "always leaned" on her for emotional support. 

"The King has always felt put-upon and misunderstood, and when he gets too self-pitying Camilla is the one who tells him to cut it out," Andersen said. "They have always been, as Camilla puts it, ‘two peas in a pod.’ They clearly get a kick out of each other, and I think that when they exchange glances and burst into laughter it's very infectious and uplifting. 

"That aspect of their relationship – the obvious affection they share and the clear fact that they are soulmates – will be good for the King and good for the future of the monarchy. That said, Camilla is no Diana." 

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