Joaquin PhoenixThe last time Joaquin Phoenix appeared on the 'Late Show with David Letterman,' the interview was testy and awkward, and helped add yet another wrinkle to Phoenix's bizarre transformation from respected actor to amateur rapper. But things are bound to get a whole lot weirder come next week.

To the delight of late-night viewers everywhere, Phoenix will be back for part deux on September 22, marking his first sit-down with Letterman since February 2009.

Casey Affleck's (faux?) documentary on Phoenix's transformation, called 'I'm Still Here,' is in theaters now and strangely enough includes the original interview with Letterman. It's very possible that Phoenix will plug the film on Letterman's show by airing a clip of himself talking to Letterman on Letterman's show. Mind blown?

Watch their last chit-chat after the jump!