This is so bizarre. Joaquin Phoenix appeared on David Letterman to promote his new movie Two Lovers. I really hope that it's a joke, but this seems too elaborate to be a stunt. He acts like he's on something, and he doesn't participate in the interview at all. I don't really think drug and alcohol abuse is something to kid around about especially when your brother died of an overdose!
The strangest part of the interview was when he couldn't remember his costar Gwyneth Paltrow's name! Letterman told him that he appears to be "taking some time off tonight." Unbelievable.