Joaquin Phoenix apologized for his infamously bizarre 2009 Late Show interview with David Letterman on Tuesday, telling Stephen Colbert, “I regret it. I’ll never do it again.”
Phoenix appeared on Letterman’s show in 2009 in character for his mockumentary I’m Still Here, complete with the shaggy beard, sunglasses, and a full suit, to talk about his big announcement that he’d be retiring from acting to pursue a rap career.
Letterman was unaware that the look, announcement, and late-night appearance were all part of the film when he sat down to interview Phoenix, and neither was the audience—resulting in an interview so weird that many thought he’d had a nervous breakdown. “It was a success and it was also just one of the worst nights of my life,” Phoenix said Tuesday.
Letterman was visibly annoyed during the awkward interview, in which Phoenix appeared distracted, answered questions in only very brief phrases, and chewed gum throughout. He also refused to introduce a clip Letterman wanted to play. The fed up late-night host told Phoenix, “I’ll come to your house and chew gum,” in one tense moment, and by the end of it, Letterman quipped, “Joaquin, I’m sorry you couldn’t be here tonight.”

Phoenix explained Tuesday why he “regrets” putting Letterman through the ringer. “It started out just in my house. I was just doing fake interviews in my house, and then we started going public,” he said. By the time he was set to appear on Letterman’s show, “I was stuck. I mean, I had to keep it going. I didn’t want to.”
Phoenix told Letterman’s producers’ his plan to come on in character beforehand, he said, and they agreed to keep the host in the dark. “I said, ‘Listen, this is what I’m doing. I’m telling you, I’m coming out here and I’m doing this whole thing. And I just want Dave to like, lacerate me. I just want it to be really dangerous.’ So that was the kind of intention. We just always wanted to get this reaction and see how I would respond to that” as his I’m Still Here character, he said. “So it was beneficial for no one to know except when needed,” he added, but “I imagine they did like a major exorcism after I left.”

Colbert replied that Phoenix should be proud: “You wanted to be lacerated, and it worked great,” he joked.
All that said, Phoenix concluded, “It was horrible. It was so uncomfortable. I regret it. I’ll never do it again. I’m so sorry,” Phoenix said, as Colbert quipped that he didn’t think Letterman was watching. “He might be. And I just need to say I’m sorry,” he said again, through a smile.
Phoenix did previously apologize to Letterman directly on air in 2010, eighteen months after he bewildered the host.

Phoenix joked to Letterman then, “You’ve interviewed many, many people and I assumed that you would know the difference between a character and a real person.” He still apologized, however, telling him “I hope I didn’t offend you in any way.”
Colbert told Phoenix Tuesday that he watched live when the 2009 appearance aired. “Those of us who do these kind of shows know that there’s something you never want to be part of,” he said, “And the phrase is ‘great TV.’ And my friend, that was great TV.”