Princess Diana and Prince Charles' "fairytale" wedding in 1981 was deemed to be the "Royal Event of the Century." However, everyone knows that their marriage was no fairytale and ended up in a very messy place.

The Princess of Wales reportedly knew Camilla Parker-Bowles ahead of her wedding to the Prince of Wales. While the Heir Apparent and Camilla broke up many years before, they remained close friends, along with her husband, Andrew Parker-Bowles.

As per Cheat Sheet, royal biographers and experts revealed that the Wales couple was a constant visitor of the Parker-Bowles household. But, five months before the royal wedding, Penny Junor revealed in his book that the now-Duchess of Cornwall sent a "letter" to Princess Diana.

It was said that the then 20-year-old soon-to-be royal found the letter on her bed inside the Clarence House. As revealed, the letter contained an invitation from Camilla Parker-Bowles for a quick lunch at a "private London restaurant." Although Prince Charles' then-betrothed knew that her soon-to-be husband and Camilla used to date, she reportedly gladly accepted the invitation and went to see Andrew Parker-Bowles' then-wife.

During the said lunch, it was revealed by royal experts and biographers that Camilla Parker-Bowles told Princess Diana that she was still hoping to spend some time with the Prince of Wales even after their wedding, especially during his hunting trips. While Camilla was believed to think that this would not create suspicions, it was said that this was the time when Diana Spencer started to figure out the true nature of Camilla and Charles' relationship.

As added by the reports, despite the Princess of Wales' knowledge about her husband's relationship with Camilla Parker-Bowles, it took many years before she "confronted" her. Express UK even noted that Princess Diana found a gift Prince Charles had prepared for Camilla just a few hours before their wedding. It was revealed to be a "gold bracelet" engraved with G and F, which were reportedly the initials that the Prince and Camilla used to call each other - Gladys and Fred.

In 1989, however, she found the courage to talk to the now-Duchess of Cornwall and told her that she knew everything about her and the Prince of Wales' affair. The details of the confrontation were reportedly learned after the "secret tapes" of the late Princess were given to royal biographer Andrew Morton.

It was claimed that Princess Diana showed up in a party that the Parker-Bowles couple' hosted. While at engagement, the late Princess was revealed to come up to Camilla, who was then talking to Prince Charles and a friend of theirs.