William and Kate, along with Harry remembered their mother 20 years on since her death in 2017. Video / AP
Princess Diana had reportedly "taken Prince Charles to the cleaners" after the royal couple finally divorced in 1996.
While they had been split for three years, it wasn't until a letter from the Queen ordering the couple to divorce that the things soon turned ugly.
On July 15, 1996, both Charles and Diana had received the paperwork to end their marriage.
Diana, who was from a wealthy family, walked away from the divorce a very rich woman, with Charles' former personal financial adviser saying she "took him to the cleaners".
She was believed to have received a lump sum of £17.5 million as well as an allowance to run her private office, which looked after her charity work and royal duties.
She was also allowed to keep living in her apartment in Kensington Palace.
But there was one strict demand Charles had when the couple decided to divorce.
Charles and Diana were separated for several years before officially divorcing. Photo / Getty Images
Geoffrey Bignell, who looked after the heir to the throne's finances for 10 years, told the Telegraph at the time: "Princess Diana took every penny he had."
Knowing she had wiped his personal funds, Bignell also revealed Charles's big demand - refusing to keep paying Diana's bills, which were piling up by the day.
From September 2, 40 of Diana's favourite stores were instructed to start sending their invoices and tabs straight to the Princess' home rather than Charles.
The legal letter read: "With effect from 2 September 1996, any expenditure incurred by or on behalf of Her Royal Highness the Princess of Wales on or after that date should be invoiced directly to the Princess of Wales's Office, Apartment 7, Kensington Palace, London."
The final divorce papers of Prince Charles, Prince of Wales, and his former wife Princess Diana. Photo / Getty Images
The couple's nail in the coffin came in the form of a handwritten letter from the Queen, which was delivered to Diana via royal messenger just weeks after she gave her tell-all interview about the breakdown of her marriage.
The Queen demanded she divorce Charles after Diana described Charles' camp as the "enemy" and said the monarchy was in desperate need of modernisation - causing embarrassment to the royal family.
The Queen wrote: "I have consulted with the Archbishop of Canterbury and with the prime minister and, of course, with Charles, and we have decided that the best course for you is divorce."
Despite being separated, Diana was against a divorce.
Diana was furious over the Queen's letter, reportedly telling her butler Paul Burrell: "That's rich! They get to decide whether I divorce!"
During the divorce, Diana's solicitor Anthony Julius urged her to give up her HRH title in a bid to get more money.
The late princess did this, but later regretted it.
