"And he was like, 'You want to know what happened? I was doing a particularly lame show; I think my guests were a ventriloquist and a guy in a monkey suit. We were wrapping it up, and there was a smattering of applause in the audience. I was having kind of a low moment, and I just said, ‘My apologies to Matt Damon; we ran out of time.’ My producer was right off camera and he doubled over laughing. It was just gallows humor. Nobody else got the joke. But it made us laugh, so we started doing it every night. I have no idea why I said you; it could have been anybody.”
For those who don't know: Damon and Kimmel have had a fake feud since Kimmel ended a bad episode of his then-fledgling talk show with a dig at the actor. Damon explained the joke to Parade:
"If you look at the picture where everybody saw the wrong tape, you’ll see Jimmy Kimmel next to Matt Damon," an insider tells Us Weekly. "Jimmy had a whole bit that got nixed obviously because of the Best Picture mix-up — he was going to do a whole thing with Matt Damon asking him what it’s like to be a loser. It was the perfect end to the night, but then obviously once the whole envelope thing happened, it got scrapped."