Casey Affleck wants to come clean.
His new movie, "I'm Still Here," was performance. Almost every bit of it. Including Joaquin Phoenix's disturbing appearance on David Letterman's late-night show in 2009, Affleck said in a candid interview Thursday.
"It's a terrific performance, it's the performance of his career," Affleck said.
He was speaking of Phoenix's two-year portrayal of himself - on screen and off - as a bearded, drug-addled aspiring rap star, who, as Affleck tells it, put his professional life on the line to star in a bit of "gonzo filmmaking" modeled on the reality-bending journalism of Hunter S. Thompson.
"I'm Still Here" was released last week by Magnolia Pictures to scathing reviews by a number of critics, including Roger Ebert, who wrote that the film was "a sad and painful documentary that serves little useful purpose other than to pound another nail into the coffin."
"The reviews were so angry," said Affleck, who attributed much of the hostility to his own long silence about a film that left more than a few viewers wondering what was real - The drugs? The prostitutes? The childhood home-movie sequences in the beginning? - and what was not.
Virtually none of it was real. Not even the opening shots, supposedly of Phoenix and his siblings swimming in a water hole in Panama. That, Affleck said, was actually shot in Hawaii with actors, then run back and forth on top of an old videocassette recording of "Paris, Texas" to degrade the images.
"I never intended to trick anybody," said Affleck, 35. "The idea of a quote, hoax, unquote, never entered my mind."
Still, he acknowledged that Letterman was not in on the joke when Phoenix, on Feb. 11, 2009, seemed to implode his own career by showing up in character as a mumbling, aimless star gone wrong.
That was just three years after he received an Oscar nomination for his spot-on performance as Johnny Cash in "Walk the Line." Memories of the film were fresh enough to induce shock in the millions who watched him on the show and in later Internet replays.
Letterman summed up the interview: "Joaquin, I'm sorry you couldn't be here tonight."
Asked whether Phoenix would be in character for his return to Letterman's program next week, Affleck said, "No, no, no." And Letterman has not talked with Phoenix about the coming appearance, he added.
Most mockumentaries, like "This Is Spinal Tap," wear their foolishness on their sleeves, leaving no doubt they are fiction. But Affleck, who is married to Phoenix's sister and has been his friend for almost 20 years, said he wanted audiences to experience the film's narrative, about the disintegration of celebrity, without the clutter of preconceived notions.