Casey Affleck on Phoenix: 'It Was Just a Performance'

Remember when Joaquin Phoenix seemingly went off the rails, turning rapper, growing a beard -- and announcing to "Extra's" Jerry Penacoli that he was quitting acting?

Apparently, it was just one of Phoenix's many performances for the documentary "I'm Still Here" -- or so says his pal, actor Casey Affleck, who made his directorial debut following Phoenix as he tried to jump start his "music career."

Affleck does credit Penacoli for playing a big part in the film when Phoenix makes his bold statement to "Extra" on-air. "Jerry, there's no one else who could have played your part, you're a genius," Affleck laughed. "It's a pivotal point in the film and you stand out, you're such a hero."

Was it a hoax? "It's not a hoax," Affleck explained. "That makes it sound like it was some silly practical joke. It was just a movie. No one ever lied to anyone. It was just a performance. People speculated, some called it a hoax, others said he's having a meltdown and needs help."

The actor/director isn't quite sure why he made "I'm Still Here," but said, "In this culture, people fixate on celebrities, build them up and beat them back down. It's interesting to me. I don't totally understand it."

If you want to take a stab at understanding it, see "I'm Still Here," in theaters now.