Princess Diana reportedly suffered from extreme temper tantrums before she wed Prince Charles.

Royal expert Penny Junor said Princess Diana and Camilla Parker Bowles got along well in the beginning. But as the royal wedding drew close, the Princess of Wales started obsessing about Prince Charles’ mistress.

“In the months leading up to her wedding, Diana changed radically. There were terrifying rages, temper tantrums, hysterical tears for no apparent reason, and her moods changed in a flash,” she said.

Junor said that Prince Charles must have taken some blame for representing Camilla as nothing more than a friend to him when he introduced them to each other.

During another incident, Princess Diana found a bracelet designed for Camilla shortly after the Prince and Princess of Wales tied the knot. Princess Diana said that Prince Charles cut her absolutely dead after she confronted her about the jewelry.

But Junor said that Prince Charles went as far as discussing the incident with Princess Diana but he still told her that she was the only woman in his life.

“The Prince of Wales is not a liar, but he gets no marks in this instance for empathy… He didn’t try to imagine how an insecure 19-year-old might feel about him giving a bracelet to the one old girlfriend she was fretting about,” she said.

And in the book “Charles: The Untold Story,” royal author Ross Benson said that Prince Charles eventually became exasperated with Princess Diana after they were asked to pose for photographs on the grounds of Queen Elizabeth’s Scottish retreat.

The paparazzi assembled close to the royal couple, but it was evident that they were both not in the mood to smile for the cameras.

Prince Charles and Princess Diana tied the knot in 1981, and they were blessed with two sons, Prince William and Prince Harry. But 11 years later, the couple publicly announced their decision to separate. They divorced in 1996.

Princess Diana and Prince Charles
Princess Diana and Prince Charles at the Chelsea Flower Show, London, May 1984. She is wearing a navy maternity coat by Jan van Velden. Getty Images/Jayne Fincher