The Walk The Line star announced plans to quit acting last year (09) and concentrate on making music. He grew a straggly beard and made a string of bizarre public appearances which led many to believe it was all a practical joke.
Phoenix's brother-in-law Casey Affleck subsequently announced he would be filming his pal's burgeoning hip-hop career for a documentary, fuelling rumours of an elaborate prank even though the pair dismissed the claims.
A one-minute clip of I'm Still Here: The Lost Year of Joaquin Phoenix surfaced online on Monday (16Aug10), leaving critics to judge for themselves.
The footage begins with an ominous voiceover, as the narrator tells Phoenix: "That's you, drops of water, and you're on top of the mountain, a success, but one day you start sliding down the mountain and you think, 'Wait a minute, I'm a mountaintop water drop, I don't belong in this valley. This river, this low dark ocean with all these drops of water.' Then one day it gets hot and you slowly evaporate into air, way up, higher than any mountaintop, all the way to the heavens.
"Then you understand that it was at your lowest that you were closest to God. Life's a journey that goes round and round and the end is closest to the beginning. So it's change you need. Relish the journey."
As the narrator speaks, Phoenix is pictured in a montage of disturbing images - including laughing manically while belted into the backseat of a car; diving off a club stage to confront a heckler; wrestling in a hotel room with another man; spitting verses with another rapper backstage while pumping his fist and wearing a hoodie, and finally in church, staring into space before taking the stage.
The movie is scheduled for release on 10 September (10).