Queen Consort Camilla and King Charles III fought for years to be together, having met decades before they tied the knot in 2005.
The pair embarked on an affair while Charles was married to Princess Diana and Camilla was with former husband Andrew Parker Bowles.
Despite the infamous scandal, Camilla and Andrew have remained close friends and continue to support each other both publicly and privately.
Andrew is currently attending the King's Coronation at Westminster Abbey and his grandchildren, Freddy, 13, and twin boys, Gus and Louis, also 13, who carried the train of Camilla's robes.
Here, we take a look back at their enduring friendship and how they became each other's biggest supporters...
Affairs
Just weeks her wedding to Charles, Diana is said to have found a parcel in the office of one of Charles' employees, and opened it to discover a bracelet.
According to royal biographer Andrew Morton, it was engraved with the letters G and F, which stood for Gladys and Fred - the nicknames Charles and Camilla used for each other.
During an interview in 1997, Diana spoke honestly about the heartbreak she felt at this moment.
She said: "I was still too immature to understand all the messages coming my way. And then someone in his office told me that my husband has had a bracelet made for her."
Camilla wore the bracelet publicly for years, even after Charles and Diana tied the knot, and Andrew is said to have been fully aware of the affair - and even approved of it.
In a 2008 documentary titled, Prince Charles' Other Mistress, royal biographer Christopher Wilson told the documentary: "It is said that an English gentleman will always lay down his wife for his country and this was certainly true in the case of Andrew Parker Bowles.
"In 1979, there was very little pretence about the intensity of the relationship between Prince Charles and Camilla.
"Most of the week he would be staying at Bolehyde Manor, sometimes Andrew Parker Bowles would come home for the weekend and Prince Charles would stay.
"But there was a very curious ménage à trois between these three."
Three years before Camilla's marriage with Andrew ended, a scandal called 'Camillagate' broke when a recording of an intimate phone call between the pair was leaked, confirming the affair once and for all.
It has since been reported that Andrew was having his own affair with Rosemary Pitman, who he later married in 1996 until her death in 2010.
Fling with Princess Anne
Prior to marrying Camilla, Andrew had a brief romance with Princess Anne in June 1970 after bonding over a shared love of horses.
They didn't make it official though, and author Sally Bedell Smith suggests this was because Andrew was Catholic, so "an unlikely candidate for marriage to a member of the Royal Family".
After their romance cooled, Camilla and Andrew began a relationship and Anne tied the knot with former husband Mark Phillips.
Despite their marriages, Anne and Andrew remained close - with him even becoming a godfather to Zara Tindall.
When Camilla later married Charles, the Queen Consort and Anne became sister-in-laws.
'Naughty' streak
Friends of retired army officer Andrew have said he is "a bit of a rogue", according to a source who spoke to The Times.
But his "misbehaving" clearly didn't cause any lasting bad blood between him and Camilla, who is said to turn to Andrew in times of need.
A close friend of Camilla's, the Marchioness of Lansdowne, said "everybody loves Andrew" and he is a "real charmer".
"Andrew will ring her up and tell her when she's got something wrong and she'll ring him up and say when he's misbehaving," she explained.
"Through adversity, they've kept a really good family ethic. It helps with their children and grandchildren."
Close friendship
Camilla and Andrew remain close friends and co-parent their two children, food critic Tom Parker Bowles and art curator Laura Lopes.
A friend of the Parker Bowles told The Times: "They are joined at the hip. He arranges so much for her. They have lunch together the whole time. He's right in there. He was always, and still is, Camilla's co-conspirator."
Andrew and Charles
Charles and Andrew's relationship goes back several decades and they even played polo on the same team.
Andrew attends major royal events involving Charles and he was even present at Charles and Camilla's wedding in 2005.
Charles, Camilla and Andrew have always been part of the same social circles and Charles is also a godfather to their son, Tom.
