Casey Affleck: People 'happy to mock' Joaquin

Says he 'never' got calls from concerned friends

Casey Affleck says people took pleasure in skewering Joaquin Phoenix while he filmed documentary, "I'm Still Here."

"The movie comes out, the critics liked to say, 'This is crazy, this is disturbing, this is sick and we should be worried about him,’ but while it was happening, people were happy just to mock him," Affleck said Tuesday on "The Tonight Show with Jay Leno."

When asked by Leno if Affleck or Phoenix -- who grew a shaggy beard and exhibited increasingly bizarre behavior -- ever received concerned phone calls, Affleck said, "Ya know, I never did."

Affleck says he knew people would eventually realize the movie was a farce.

"I wanted them to think it was real while they were watching it," he told Leno. "But I assumed, when it was over, they would understand that it wasn't real."

"We just wanted to make a movie that would help people kind of suspend their disbelief. They could go to the theater; they could experience it -- sort of wonder whether it was real or not," he added.

Don't call the film a "hoax," he says.

Says Affleck: "It's not a documentary, because all the people in the movie are acting... A social experiment, if you want to call it that. I would call it a, uh, movie."