In 1995, Princess Diana claimed in a scandalous interview with Martin Bashir in the UK that there were "three people" in her marriage - highlighting Prince Charles' past with Camilla. Following the interview, the Queen wrote to both Diana and Charles advising them to get a divorce. When news broke about the divorce, it shocked the world.
According to The Sun, the Princess of Wales confided in late singer George Michael, revealing that the royal family was "not very loving" and that her breakup had been "grim".
However, recently unearthed letters exchanged between Prince Philip and Diana show that the Duke of Edinburgh appeared to take his daughter-in-law's side when things soured between her and Charles.
In a letter allegedly written in 1992, Prince Philip revealed to Diana that he and the Queen disproved of their son's love life, "Charles was silly to risk everything with Camilla for a man in his position,"
"We never dreamt he might feel like leaving you for her. I cannot imagine anyone in their right mind leaving you for Camilla. Such a prospect never even entered our heads."
The letter was signed off with a touching, "with fondest love, Pa."
It has been suggested that Philip offered to act as a mediator between Diana and Charles during their bitter divorce, reportedly writing, "I can only repeat what I've said before, if invited, I will always do my utmost to help you and Charles to the best of my ability,"
"But I am quite ready to concede that I have no talent as a marriage counsellor."
Prince Philip made it clear to Diana that he would not support her or Charles if either pursued new romantic relationships, writing, "We do not approve of either of you having lovers."
Princess Diana's private security Patrick Jephson alleged that Diana's in-laws' support meant a lot to her. However, it is claimed that Philip questioned Diana by asking her if, "Charles's relationship with Camilla had nothing to do with your behaviour towards him in your marriage?"