Why does Jimmy Kimmel always say, "Apologies to Matt Damon"? at the end?

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Jimmey Kimmel (late night show host, USA) always closes his show with an apology to Matt Damon. And, I've always wondered why. Maybe he missed the chance to interview Matt years ago and has been apologizing ever since. Anyway he likes to play jokes on Matt Damon and got one of his cast members to pretend he wanted to interview Matt at a movie premiere. When Matt finally came over for the interview the person said, "Sorry to Matt Damon, we're out of time. Back to you Jimmy." It was hilarious. Matt figured out who was pranking him though. Later Matt got him back by making a spoof video with Jimmy's girlfriend. It was very explicit and funny. If you haven't seen it yet, let me know and I'll post the link. So, back to my question. Why does Jimmy Kimmel close out his show with an apology?