Maybe it’s the beard. Maybe it’s the gut. Maybe it’s the ridiculous indulgence in cocaine, cigarettes, strippers and rap music, but something about “I’m Still Here” is unbelievable—which is exactly what Joaquin Phoenix wants the audience to think.

In 2008, Phoenix announced his retirement from acting, but that wasn’t what had people questioning his sanity. Phoenix made it widely known that he was leaving acting to pursue his dream of rapping. The Oscar nominee immediately drew massive amounts of attention, and clips from his rap performances began to circulate on YouTube. Phoenix’s increasingly erratic behavior culminated with a disjointed, incoherent interview on David Letterman’s talk show, causing viewers to wonder who this new man was.

It turns out Phoenix didn’t lose his mind, but he’s just been in character for the last two years. Phoenix’s brother-in-law, also the director of the film, Casey Affleck, acknowledged that the film had been staged after its release in September. A handful of other well-known performers, including Ben Stiller, Jamie Foxx and Sean “Diddy” Combs, were also in on the joke.

The film is an experience in and of itself. The new Phoenix, or “J.P.,” as he calls himself, is a pudgy, hairy, disheveled-looking version of the celebrated movie star. Frequently shown yelling, cursing and generally making an idiot out of himself and his employees, Phoenix pulls out all the stops. And whether he’s engaging in illicit drug use with prostitutes  or jumping off of a stage onto an audience member, an ever-present cigarette always accompanies his antics.

Combs’ cameo in particular adds an additional element of insanity to the film. After repeatedly calling Combs and following him from California to New York to Florida, Phoenix finally schedules, and is on time to, a meeting with the hip hop producer. Phoenix puts in his CD and starts to sway to the sound of his voice, which is undecipherable. Even as someone aware that the film was staged, Combs’ reaction steals the scene.

“I’m Still Here” is utterly shocking, yet completely enjoyable. The dreadlocked, highly distressed J.P. is one of Phoenix’s most fascinating characters to date.