There are some people in Hollywood who don't need a designated day to prank the crap out of everyone they know.

Today is April Fools Day, and while we might be on edge waiting to get pranked at the office or on Facebook, these A-listers keep friends and loved ones on their toes 365 days a year. From ladybug ambushes to gay rumors, check out our roundup of the 12 best celebrity pranksters ever -- and their most infamous gags!

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1. Johnny Depp

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Talk about being dedicated to your craft. While filming the movie Blow with Penelope Cruz, she revealed that he purchased a remote controlled fart machine and kept making noises with it during her most serious lines in the film. "I was doing a very dramatic close-up [and] he kept making that sound with the machine." Hasn't he ever heard of a whoopie cushion or the old hand in the armpit?

2. Brad Pitt

This was less of a prank and more of an effed-up ambush, but it's still pretty epic either way. After throwing a party at a posh Mexican resort for all of his friends, Brad bribed the government to cut the hotel's power at exactly midnight. Not only that, but he then sent in heavily armed troops to storm the grounds SWAT style and arrest one of his friends on bogus drug trafficking charges.

3. George Clooney

George is known as the messiah of pranking among Hollywood's elite. While living with fellow actor Richard Kind, he found a dingy painting in a trash pile near the apartment they shared together. He picked it up, signed his name and presented it to Richard as though he painted it. His friend hung the painting on the wall and kept it there for two years before George finally came clean.

4. John Mayer

Even during his douchey days, John was still good for a comedic moment now and again. While on tour with Sheryl Crow, he walked out on stage to sing a duet with her in a bear costume.

5. Ryan Kwanten

In addition to lots of fake blood and scantily clad bodies, the True Blood set is also full of pranks put on by Ryan. According to co-star Jim Parrack, the actor "took our cameraman's car and filled it with ladybugs. He goes all out ... I think if Ryan could retire from acting and be a prankster, he would consider it."

6. Matt Damon

Matt looks pretty sweet, but it's obviously just for show. During the Venice Film Festival, he "outed" George Clooney and claimed he had a boyfriend that he was planning to marry as soon as it was legal. He even managed to punk Jack Nicholson of all people! When Jack had to go into the hospital to get his salivary glands fixed, Matt reportedly dressed up as a medical intern at the hospital and told Jack that he needed to be given a rectal exam.

7. Josh Huston

The legendary actor and film director once flew a plane over a celebrity golf tournament in Mexico and dropped 2,000 ping pong balls with phrases like "Go home you Yankee sons of bitches." The mess caused so much damage that the tournament had to be cancelled and took days to clean up.

8. Mel Gibson and Jodie Foster

Mel Gibson and "funny" don't usually go in the same sentence these days, but the notorious rageaholic was more humorous at one point. While shooting Maverick with Jodie, he reportedly rewrote the script with cheesy sexual dialogue for her. In return, she hired a bagpiper to follow him around on set and play right in his ear.

9. Paul Newman

In one of the most extreme pranks ever, Paul apparently took some serious offense to director George Roy not buying everyone a round of drinks after wrapping shooting on Cool Hand Luke. He decided to stage a fake car crash and got people to tell George that he was behind the wheel. When the director raced to the scene of the "accident," Paul was right there waiting to laugh in his face.

10. Justin Bieber

This may not be our idea of a prank, but Justin seems to think that mooning people on Instagram and wearing a gas mask in public counts as such. However, he's also pulled off some good ones on his fans.

11. Will Ferrell

Back in 2008, Will showed up to a football game at his alma mater, the University of Southern California, dressed as Captain Compete. Wearing a stained, ill-fitting costume, he saved the day by dousing a "burn victim" with Gatorade well after the fire was put out.

12. Ashton Kutcher

Punk'd, anyone? It's one thing to be a prankster, but it's a whole other thing to make millions off it.

Which celebrity prank do you think was the funniest?

Photos courtesy of Getty Images and CNN