Over a matter of mere months, Phoenix has gone through a series of drastic cosmetic changes - most noteworthy is the scraggly beard and long, dishevelled hair - to become the lesser-spotted 'grizzly man'.
Visual aid:
Joaquin,
before
and
after
the 'grizzly' intervention
The star's drastic transformation, he insists, is all part of his master plan to discover his true self - which apparently involves ditching the thespian antics and taking up rapping instead.
And to prove that he's serious about his new career, Phoenix performed at Las Vegas club LAVO over the weekend, and showcased a handful of his new tunes. Let's just say that his performance was interesting...
Decked out in his new hobo-chic get-up, Phoenix positively bombed. Check out his memorable and cringeworthy appearance below:
And it gets worse.
As he bobbed along the catwalk at the end of his 'performance', Phoenix was left red-faced as he ate the stage and fell into a deep chasm from whence he came.
Yep, that's what you call biting it.
But despite the decidedly lukewarm reaction to his foray into music, Phoenix says the show will go on.
He tells People.com, "This is me saying this is who I am. This is my story. After all the years of reading scripts and reading lines, this is my chance to do something straight from the heart and put it out there.
"When I was young I liked punk rock music but then I discovered rap. I love the storytelling aspect of hip-hop.
"Are there people out there who think I'm a joke? I'm sure there will be. Are there people who think it's going to suck? Probably, but I can't worry about that."
Other cameras were there to capture the action, too. His brother-in-law, Casey Affleck (Ben's little bro who's married to Phoenix's sister Summer) reportedly filmed the musical foray for a doco to be released at a later date.
But the fact that Phoenix has chosen to document his transformation through the eye of a lens has led many to question whether the whole thing is one Borat-inspired gag.
Gag or not, there's no denying that Phoenix's antics are beguilingly entertaining - even if he does look like he needs a flea dip.
Joking aside, some say that what we're witnessing is Phoenix's very public meltdown. A snitch tells the Mail Online: "For people who know Joaquin, it's been an incredibly traumatic year, filled with chaos.
"Everyone wants to help but nobody's been able to break through. His bizarre behaviour has everyone worried. It's just getting scary.
"Joaquin has rejected everything that has come along with Hollywood stardom, the acclaim, the attention, and the artistic opportunities."
Phoenix's first album is rumoured to be produced by Sean "Diddy" Combs. Says so
here
.
Video: Phoenix on his road ro rap
The plot thickens...
BBB
Pictured above: A dishevelled Joaquin Phoenix declares his retirement from acting and, inset, during his grooming days. Photos AP/ Daniela Catelli