Princess Diana previously stunned in the iconic revenge dress that she wore to an event after Prince Charles confessed to having an affair with Camilla.

But royal biographer Andrew Morton said that the iconic ensemble almost never happened. While speaking with Daily Mail, Morton said that Princess Diana had a change of heart at the last minute.

On the day of the party, the Princess of Wales was already set on wearing a Valentino dress to Vanity Fair’s party. But she decided to not to do so after learning that the fashion brand announced that Princess Diana would wear one of their creations. The Princess of Wales thought that the move was presumptuous.

Princess Diana’s good friend, James Colthurst, advised the royal to wear something more daring to the party even though he had absolutely no clue about fashion.

“She said to him she was so annoyed with Valentino, and he said, ‘Well, I don’t know, look, wear something else, something sexy.’ She said, ‘I probably will,’” Morton said.

Although Princess Diana feared that the dress, designed by Christina Stambolian may have been too daring, she actually made royal fashion history with it. The public called the black form-fitting dress as the “revenge dress” because Princess Diana stunned in it after Prince Charles’ shocking confession.

Prince Charles and Princess Diana had already been separated for two years after the confirmation came straight from the horse’s mouth. And two years later, the couple decided to divorce legally.

However, Princess Diana’s life after her divorce from Prince Charles became short-lived. She died on Aug. 31, 1997, just one year after their marriage ended, and she has been missed by her sons, Prince William and Prince Harry, and her royal fans. At that time, Princess Diana was with her boyfriend, Dodi Al Fayed.

Until today, Princess Diana gets widely talked about by her supporters. And her revenge dress is forever etched in their hearts.