Joaquin Phoenix: Professional Beardo (February 11th, 2009)
"You look different than I remember you," said Letterman to the Oscar-nominated star, and it was safe to say he was speaking for everyone who'd tuned in to see Phoenix sporting a hermit's beard, sunglasses and shabby black suit. After mumbling about retiring from acting so he can pursue a hip-hop career and thouroughly alienating everyone — including the host — Letterman cracks "Well, I'm sorry you couldn't be here tonight, Joaquin." Now, we know that whole interview was part of a performance art-cum-film project that Phoenix was working on ("I'm Still Here"), and the star would eventually return to the show a little over a year later to apologize. At the time, however, it was simply one of those can't-watch-can't-look-away car-wreck appearances that had become hallmark of The Late Show.