Prince Charles and Princess Diana
Princess Diana and Prince Charles attend a welcome ceremony in Toronto at the beginning of their Canadian tour on Oct. 1, 1991. Getty Images/Jayne Fincher

Prince Charles and Princess Diana’s tumultuous marriage ended in divorce in 1996. But prior to this, the royal couple first had a trial separation in 1992.

According to royal author Penny Junor, it was during this time that Princess Diana humiliated Prince Charles publicly following the release of “Diana: Her True Story.” In the book, Princess Diana basically aired her dirty laundry to Andrew Morton.

After reading the book, Prince Charles urged his friends to not say anything against his wife. He also refused to publicly humiliate the late royal in the same way that she humiliated her. The heir to the throne decided that he won’t retaliate.

But Junor said that whenever she would tell people that Prince Charles never publicly criticized Princess Diana no matter how bad their relationship was, the public would automatically assume that this was because the future King had friends who did the criticizing on his behalf.

However, “The Firm” author said that this wasn’t necessarily the case. “Some of his friends did feel that the injustice meted out to him by Morton’s book was intolerable and I, for one, was encouraged by several of them to try to redress the balance, but they were not thanked for their trouble and neither was I,” Junor said.

But just two years later, Prince Charles also had the opportunity to share his version of events and his side of the story during his interview with Jonathan Dimbleby. Junor said that she was the one who was supposed to interview Prince Charles at that time, but she was dropped from the project.

“[Producer] Christopher Martins and I had been to a private lunch at Highgrove to discuss it with him. Suddenly I was dropped from the project and discovered very much later the reason why – I had defended him too vigorously in the media,” she revealed.

And in the book “The Diana Chronicles,” royal author Tina Brown said that if Princess Diana didn’t agree to an interview with Morton in 1992, Prince Charles would have never spoken to Dimbleby about his marriage. And Princess Diana wouldn’t have fired back with her Panorama interview.

“And together, the interviews locked the royal protagonists into a course of no return,” Brown said.