This week, the late royal's former personal chef Darren McGrady revealed that Diana misled pal Oprah Winfrey by letting the media mogul eat a super-fatty meal while Diana ate a fat-free version of the same dish without telling Winfrey the truth.
And until know, news of Diana's food prank had been kept a royal secret!
While this may be our favorite celebrity prankster story of the week, Diana surely isn't the first star to play tricks and enjoy jokes. Here are six other super-awesome celebrity pranks.
1. Sacha Baron Cohen's Geriatric Jest: While presenting at the 2013 BAFTA Britannia Awards in Beverly Hills, the well-known prankster shocked the audience when he pushed an elderly woman in a wheelchair off the stage and onto the floor below! Seconds later (after many gasps), it was revealed the woman was an actress and not Grace Cullington, the last living actor to have worked with Charlie Chaplin.
2. The Ultimate Prankster: Known for his on-set antics, George Clooney revealed his favorite wardrobe prank, which he pulled on BFF Matt Damon during the filming of their flick The Monuments Men. "He shows up on the set, he's like, 'I wanna lose 15 pounds on this movie,'" Clooney said of Damon. "So he's dieting and exercising. He would go away for a week and I would just have the wardrobe people take in his wardrobe half an inch. By the end, he's just like eating a grape, but his pants are getting tighter."
3. Amber's X-Rated Joke: While filming a steamy sex scene with her Paranoia costar Liam Hemsworth, Amber Heard tricked the hot Aussie actor by bringing a sex toy into their bed. When he went to reach for her arm, he grabbed a dildo instead! "It's not a little prank," Heard winked at the film's premiere. "It was a big prank."
4. Holiday Overload: Just before the 2013 holiday season, funnyman Jimmy Kimmel revealed on his show, "Around the holiday season, I have a tradition, and that tradition involves vandalizing my friend John Krasinski's home." Kimmel then showed a video in which he secretly covered Krasinki and Emily Blunt's house with hundred of decorations, much to the surprise of the celeb couple, who weren't home at the time.
5. The Biebs Fools the World: In October 2012, Justin Bieber pranked everyone by fooling fans into thinking his computer had been stolen. Soon after, an alleged nude pic of the pop star made it's way online. However, the whole thing was an elaborate PR stunt leading up to the release of his single "Beauty and a Beat" featuring Nicki Minaj.
6. I'll Be Back: In 2014, Arnold Schwarzenegger returned to his former training facilities at Gold's Gym in Venice beach to prank people while disguised in a black wig and fake mustache. Who would have thought his signature accent would eventually give him away to gym members?