Casey Affleck: Joaquin Phoenix film is performance art

Casey Affleck Thursday conceded that his Joaquin Phoenix "documentary" feature "I'm Still Here" was, in fact, part of a two-year piece of performance art in which Phoenix, both on- and off-screen, portrayed a rambling, mumbling, bushy-bearded and substance-abusing actor on the verge of a nervous breakdown.

"I never intended to trick anybody," Affleck, 35, told The New York Times. "The idea of a quote, hoax, unquote, never entered my mind" - though he had pledged at the Venice Film Festival earlier this month, "I can tell you that there is no hoax."

Affleck said hints of a mockumentary were scattered throughout the film, which was released last week to mixed reviews, scoring a middling 57 percent positive based on 78 critics at the aggregate site rottentomatoes.com. The raw camera style at the start of the film, he said, gave way to more sophisticated technique later in the narrative.

Sequences of Phoenix, also 35, with drugs, prostitutes and a purportedly traitorous assistant "were multiple takes, these are performances," Affleck said. Supposed shots of the star and his siblings swimming in a Panamanian water hole were actually filmed in Hawaii with actors - and distressed for a home-movie look, Affleck said, by recording it onto an old videocassette of the 1984 Wim Wenders film "Paris, Texas" and then running it back and forth on a VCR.

"We wanted to create a space," Affleck said. "You believe what's happening is real."

The ostensible performance extended to Phoenix's befuddled appearance on "Late Show with David Letterman" in February 2009 - in which the talk-show host memorably quipped, "Joaquin, I'm sorry you couldn't be here tonight."

Phoenix, an Oscar nominee for his role in the Johnny Cash biography "Walk the Line" (2005), is now seeking legit movie roles, according to the trade press.

In the meantime, Affleck says of the apparent act, "It's a terrific performance; it's the performance of his career."