princess diana
Britain's Princess of Wales arrives at her London health club. Johnny Eggitt/AFP/Getty Images)

Princess Anne was reportedly never fond of Princess Diana. But the two female royals’ relationship took a turn for the worse following one incident.

In the book “Prince Edward,” royal author Ingrid Seward detailed an encounter between the Princess Royal and the Princess of Wales. Seward said that certain occasions within the royal family are regarded with utmost importance. One such event is the christening of a newborn royal family member.

“Such occasions are a cornerstone of the royal family’s routine, and essential part of the theatricality of their brand of monarchy; a moment when the whole family is on parade. It would never have occurred to Edward or any of his family not to turn out for one… Diana, however, chose not to attend,” Seward said.

Princess Diana was invited to attend Zara Tindall’s christening decades ago. But since the baptism was held just days before she and Prince Charles tied the knot, the mom of two said that she couldn’t make it because she was busy.

But it was, later on, revealed that there was another reason why Princess Diana refused to attend Tindall’s christening. According to Seward, Princess Diana knew that Camilla Parker Bowles would be there because the latter’s then-husband, Andrew Parker Bowles, was one of Tindall’s godparents.

The royal author also revealed that Princess Diana had already been telling her friends that she won’t attend Tindall’s christening. But it was only two days before the event that she informed Princess Anne about it. The only daughter of Queen Elizabeth II and Prince Philip reportedly then gave Princess Diana a chilling response that could’ve frozen the Arctic.

“While the other [members of the Royal Family] were prepared to give Diana the benefit of the doubt, Anne was not. Self-contained and matter-of-fact to the point of ruthlessness, she had no sympathy for Diana’s temperamental maundering,” Seward said.

Princess Anne and Princess Diana never patched things up since then. But the two appeared civil while they were out in public.