What has happened to Joaquin Phoenix?

To stray away from politics for the moment, I was watching letterman last night and was shocked to see Joaquin Phoenix say he's becoming a rapper and quitting acting. He looked all drugged out. It's sad, he's such a good actor. Loved gladiator, walk the line and ladder 49. Some think this is just a PR stunt and not real but that doesnt seem to be the case..

"There's not a hoax," ... "Might I be ridiculous? Might my career in music be laughable? Yeah, that's possible, but that's certainly not my intention"