Most Uncomfertable Letterman Interview?

This has easily got to be the most uncomfortable five minutes on David Letterman ever. Oscar-nominee Jaoquin Phoenix showed up with an ugly beard, giving one word responses and...well, I don't want to spoil it for you, so just check it out:

I don't know what's with this guy. Seriously. He says he intends to retire from acting and start a hip hop career. Well, after seeing his first live performance...

...I have to agree that no matter how much he assures us he's serious, this comes off as a big joke. I guess we'll have to wait and see.