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By Michelle Lanz

Well folks, we can finally solidify what we've known all along: Casey Affleck's "documentary" about Joaquin Phoenix's breakdown and transformation from actor to hip-hop star was nothing more than an elaborate piece of performance art. A hoax, if you will.

At this point it's safe to assume that the majority of the movie-going public had at least a strong hunch that "I'm Still Here" was fake and that there was something incredibly contrived about Phoenix's erratic behavior. Yet the public couldn't be one hundred percent certain of its authenticity, because it took two whole years for the filmmaker to unveil his ruse.

Just a week after the film was released in theaters, Affleck has come clean. The hype has already begun surrounding Phoenix's upcoming guest appearance on "The Late Show with David Letterman" show next week. The New York Times reports that Letterman was in on "the joke" back in Feb. 2009 when Phoenix acted like a complete weirdo. Now that it's all out in the open, the question is whether this ambitious project was worth the potentially alienating effect it could have on both men's careers and personal lives.

RELATED: Scoop: Affleck admits Phoenix film a hoax

"We wanted to create a space," Affleck told the New York Times in a Sept. 16 article. "You believe what's happening is real." In the beginning, there was always the chance that Phoenix was actually losing his mind. After all, crazier things have happened in Hollywood. But as months and years went by, interest in whether it was true or not waned to the point of complete indifference.

The major problem with the whole execution of "I'm Still Here" is timing. The film was released on Sept. 10, some two years after Phoenix began his mountain man metamorphosis. The chatter died down long ago and potential audiences for the film have already become either bored with the spectacle, disinterested in its veracity or decided long ago that it was just a hoax anyway.

Had they released the film soon after the buzzworthy and relatively convincing David Letterman fiasco, perhaps enough of us would be invested enough to care or actually see the film. At this point, Phoenix's supposed turn as a hip-hop star is such old news, perhaps they ought to have changed the title to "I'm Still Here?"

RELATED: Watch the 'I'm Still Here' Trailer

Then there are the personal repercussions of the whole charade. Phoenix went from Oscar-nominated A-lister to disheveled lunatic for two years. He hasn't acted in anything but this documentary during that time, which shows an intense and commendable loyalty to the project, but might not have been the best move professionally.

Casey Affleck managed to show up in a film this year, the brutally violent "The Killer Inside Me," but he got entangled in a dual sexual harassment suit with two women from the production team of "I'm Still Here." News came this week that the case had been settled out of court, but no word on the payout.

Seriously, what was the point of these shenanigans? Affleck insists that he "never intended to trick anybody" and that "the idea of a 'hoax' never entered my mind." Surely he's kidding ... right?

RELATED: Phoenix asks Diddy for help in 'I'm Still Here'

When Phoenix made his bizarro appearance on "The Late Show," and Letterman played along, were we to believe that it was NOT done with the intent to trick the masses? Should we all assume that it's OK for a documentary filmmaker to promote a film as truth when it's truly complete fiction?

I understand Affleck's attempt at "gonzo" filmmaking, named after late journalist Hunter S. Thompson's work, which had loose associations with accuracy. The difference is that Thompson was clear and deliberate about what he was doing, as were professional pranksters like Sacha Baron Cohen and late comedian Andy Kaufman. Affleck and Phoenix passed their film as truth and end up as just a couple of boys who cried wolf.

Fessing up after all this time and using the euphemism "performance art" is just another form of telling us what we already know. So is this a hoax or an art piece? Is it a hoax as an art piece? Or is it just a misguided (and lengthy) prank? Maybe it's all of these things, and maybe Phoenix's alter ego has overshadowed the real man and artist within.

Follow Wonderwall Editor Michelle Lanz on Twitter!