Remember when Joaquin Phoenix grew out a beard and acted all crazy in 2008? Well, the product of his odd behavior is officially here!

Casey Affleck's "movie" I'm Still Here - which chronicles Phoenix transitioning from actor to rapper - hits the big screen on September 10th.

Its distributor Magnolia Pictures insists the pic is not a mockumentary... er, so what is it then?

Director Affleck filmed all of Phoenix's bizarre outbursts and public appearances for the doc, which many believed to just be a big hoax.

Guess everyone can decide for themselves come September!