It's that time of year again: April Fool's Day. And you know what that means? New pranks! Ah, yes, a day full of walking cautiously around corners and double checking to make sure someone didn't switch the table salt out for sugar. While the art of the prank is only officially celebrated one day a year, there are some celebrities who treat every day like its Apr. 1.
For example, Jimmy Kimmel and Matt Damon's prank war has been going on for over a decade. What started off as a little joke in 2006 (there isn't ever enough time on Jimmy Kimmel Live! to get to Matt on the air) has now escalated into one of the longest-running celebrity wars of all time.
Most recently, Jimmy got Matt during the 2017 Oscars. Jimmy started the bit by first doodling elf ears on Matt's seating card, then posting it on social media for everyone to see. It didn't stop there, though! Jimmy topped it off during the live show by instructing the orchestra to play every time Matt tried to speak while presenting Best Original Screenplay with Ben Affleck. "You can't play me off," Matt yelled over the music. "I'm just presenting!"
From ongoing wars like Jimmy and Matt's, to Ashton Kutcher's show Punk'd (which played jokes on dozens of celebrities and even made Justin Timberlake cry), some stars really have perfected the art of the prank. Here are the 15 celebrities—George Clooney included!—considered to be Hollywood's royal jesters and biggest pranksters.