Joaquin Phoenix says there's no hoax about it: He really has given up acting to become a hip-hop musician.

Phoenix has been spending his time laying down tracks for a rap album in the recording studio he built at his home, the two-time Academy Award nominee said Tuesday in an interview to promote what he claims is his final movie, "Two Lovers."

After video hit the Internet last month capturing part of Phoenix's debut rap performance at a Las Vegas club, speculation swirled that he was perpetrating an elaborate practical joke.

"I don't know where that comes from," Phoenix said. "If it comes from people that I've had a falling out with, that are (ticked) off at me?"

The video shows Phoenix, in a long, scraggly beard, rapping nearly inaudibly and ends with him losing his footing and falling off the stage. It was an inauspicious start, but Phoenix was adamant that his hip-hop career is real.

"There's not a hoax," Phoenix said. "Might I be ridiculous? Might my career in music be laughable? Yeah, that's possible, but that's certainly not my intention."

Phoenix's friend and brother-in-law, Casey Affleck, was on hand with a camera crew as he did interviews for "Two Lovers." Affleck, who is shooting a documentary about Phoenix's transition to music, said his friend is completely serious.

Phoenix, 34, said he had not expected anyone to care when he made the surprise announcement last fall that he was quitting Hollywood for music. At the time, fans assumed he might build on the country roots he laid down playing Johnny Cash in "Walk the Line," on which he learned to play guitar and did his own singing.

His new rap persona added to the confusion, but Phoenix said he is a longtime fan of hip-hop, speaking fervently about Public Enemy, Ice Cube and other artists he admires.

Phoenix said he has no intention of returning to film after "Two Lovers," a romantic drama co-starring Gwyneth Paltrow and reuniting him with James Gray, his director on "The Yards" and "We Own the Night." The movie opens Feb. 13.

While Phoenix regrets that his coming-out party as a rapper came through poor-quality video over the Internet, he said people would have ridiculed him no matter how good his debut was.

"It sucks that, yeah, the footage is out there as like this incredibly bad sound, and you literally can't hear what's happening," said Phoenix, who still has his bushy beard. "It was much better in the club, and I don't know who said that people were booing ... because that was not happening.

"Unless, of course, it's a pretty big place, and maybe it was happening," Phoenix added, laughing. "But it was not my experience. My experience afterward was I had a lot of dudes come up and say, `We really respect you for doing it, putting yourself out there, and going with it.' Because I think true hip-hop heads know that it's hard, it's going to be a hard transition, and people are going to be lining up just to make fun of me."