A new book has revealed that Prince Charles allegedly made an “offensive” comment about Princess Diana just days after she died in a car crash in Paris, France back in 1997 at the age of 36.

In his book “Battle of Brothers: The Inside Story of a Family in Tumult,” author Robert Lacey claimed that Charles made the comment to Diana’s brother, Charles, 9th Earl Spencer, as they tried to plan Diana’s funeral. They reportedly feuded over arrangements for the funeral, with Spencer objecting to Charles’ plan to have his sons Prince William and Prince Harry walk the entirety of a public funeral procession behind their mother’s casket.

“Prince Charles had no doubt that he should walk the long route with both his sons beside him,” read an excerpt of Lacey’s book that was obtained by People Magazine, “But Uncle Charles Spencer did not agree. He was already angry on his family’s behalf that his sister’s funeral had been hijacked into a royal occasion, and he was particularly opposed to the idea that his young nephews should have to walk the best part of a mile behind their mother’s coffin through the streets.”

“Spencer felt quite sure that Diana would have been horrified at the idea of her sons having to endure such an ordeal,” Lacey continued. “He had already told Charles as much.” One contentions call between them “had ended with the earl slamming down the phone on his brother-in-law after Charles had made a particularly offensive comment about Diana.”

When it finally came time for the funeral, William and Harry did end up joining their father, Spencer and their grandfather Prince Philip for the lengthy procession.

Twenty years after the funeral, Harry opened up about how traumatic it was for him and his brother.

“My mother had just died, and I had to walk a long way behind her coffin, surrounded by thousands of people watching me while millions more did on television,” he said “I don’t think any child should be asked to do that, under any circumstances. I don’t think it would happen today.”

During the funeral, Spencer delivered a powerful eulogy for Diana, calling his sister the “very essence of compassion, of duty, of style, of beauty.” Spencer went on to vow that “we, your blood family, will do all we can to continue the imaginative, loving way in which you were steering these two exceptional young men, so that their souls are not simply immersed by duty and tradition but can sing openly as you planned.”