Prankster George Clooney's penchant for sending out cards and letters from his famous friends began at John Krasinski's wedding in 2010. Matt Damon recently discovered that his Ocean's Eleven co-star has been sending stationery with his name on it around Hollywood for several months as a practical joke, but Brad Pitt was the first star to suffer. During an appearance on fellow prank lover Jimmy Kimmel's U.S. TV show, Clooney revealed the comedian had been involved in the elaborate joke that began when they met up at their mutual friend's wedding party, which was held at Clooney's villa in Italy. He said, "You sent me a thank you gift card... it actually said Brad Pitt on it, which set the wheels in motion... I've been sending letters to people as Brad Pitt for four years. "Don Cheadle was trying to do the Miles Davis story and I sent him a letter from Brad, because Brad produces films, and I said, 'You know, I'm producing this Miles Davis/Charlie Parker thing and Jamie Foxx is gonna play Miles Davis, but you'd you'd be great as Charlie Parker?' "Don wrote me, like, six months later and said, 'Did you do something dirty to me?'" Clooney revealed his most elaborate 'note' prank came when he sent Meryl Streep a package of dialect tapes from Pitt and urged her to use them to help her perfect the role of Margaret Thatcher in The Iron Lady. The Michael Clayton star chuckled, "I said, 'To Meryl, I hear you're gonna play The Iron Lady and this guy really helped me with my dialect in Troy'. I never told either of them I did that. Now they know." Clooney's interview with Kimmel aired in the U.S. on Thursday night (06Feb14).