Everyone's been debating whether Joaquin Phoenix's crack-up, as evidenced on Letterman the other night, is real or a hoax. It sure looked real to the director of his last movie.

James Gray, who directed Two Lovers and is also close to Phoenix personally, told ABC News Radio, "if it's an act, it's the most committed act I've ever seen in my life."

"I mean, he built this studio [in his house]. The lengths to which he's taken it are quite extreme."

"Toward the end of the shoot, he kept saying 'Oh I'm so tired, I'm so tired.' You hear that kind of thing and you think it's a joke," he said. "I just ignored it."

Gray said Phoenix got into rap after Gray played the actor some unspecified recording relating to his own teenaged freestyling. "He said, 'I want to do that, I want to steal from that."

Now Gray feels guilty, because Phoenix quit acting. "I feel like I've ruined Joaquin Phoenix for the world."

More worrisome than Phoenix's career switch is the possibility that he's gone off the deep end. Maybe he did so intending it to be part of a hoax, maybe not. But if he's drowning does it really matter?

(Counter theory: It's just a hoax and Gray, who by his own admission is Phoenix's buddy, is in on the whole thing.)