As the new Joaquin Phoenix flick "I'm Still Here" hits theaters, director Casey Affleck has come clean that the film is a performance ... not a documentary.

I reviewed the film this week, giving it a strong thumbs up whether it proved to be real or fake. These new revelations ought to get people talking about Phoenix's bizarre performance.

If you're adventurous (the film is pretty out there on several fronts), you definitely should check it out this week. It's playing exclusively at the Gateway Film Center. For a taste, check out this clip of Phoenix meeting Diddy to discuss producing his rap album.