My thoughts, if you care to know, are that he's pulling an Andy Kaufman, especially when you consider that his brother-in-law, Casey Affleck, is supposed to be filming his transition from movie star to hip-hop artist. Compare the above clip with the below previous appearance on Letterman:
Night and day. If he's not attempting to pull off a Kaufman then, he's not in a good place. Regardless, it's made me interested in his album and if and when his debut album comes out I'll more than likely download it on itunes. So if this is all an elaborate self promotion stunt, and I sincerely think it is, it's working, at least on me. Furthermore, if he is pulling a Kaufman, and again I sincerely hope that's all this is, kudos and brilliant.