Joaquin Phoenix made a strange appearance on David Letterman's Late Show on Wednesday night to promote his film Two Lovers. Phoenix was unresponsive for most of the interview, giving odd, one-word answers for other questions. He claimed he's retiring from film to devote himself to his hip-hop career. At one point, he takes the gum out of his mouth and sticks it to the host's desk. Finally, Letterman ended the interview with, "Joaquin, I'm sorry you couldn't be here tonight!" To see the interview, go to: https://www.cbs.com/late_show/video/.