Oscar nominated actor Joaquin Phoenix is at it again. This time he hit up David Letterman's late night show to further sell his latest career move into hip-hop artistry. Decked in a black suit and sunglasses, Phoenix was billed to promote what he says will be his last film, 'Two Lovers.'

Instead, he confirmed with Letterman that he would in-fact be pursuing a rap career, amidst audience laughter. "I'd love to come on your show and perform," he said. Letterman responded saying that a performance wasn't likely but that he would "keep him in the Rolodex."

Phoenix appeared unimpressed with Letterman's gags. "Can you tell us about your days with the Unabomber?" Letterman joked. "Are you f---ing kidding? Are you serious, with the maniacal laughter?" Phoenix said to the show's band leader Paul Shaffer, who also couldn't keep from laughing. Letterman ended the interview by saying "Joaquin, I'm sorry you couldn't be here tonight."

Last month Phoenix announced that he was retiring from acting to pursue a rap career. While the press seems to think he's pulling their chain, the 34-year-old is sticking to his guns. "When music replaced acting for me, there was no turning back," he said in an interview. His "cross-over" has been rife with speculation stemming from half-hearted performances, a rumor that he may be working with music mogul Sean "Diddy" Combs, and a video of him falling off stage during a show. All the while, Phoenix's brother-in-law Casey Affleck has been videotaping his transition for a documentary centered around his career change.

The younger brother of the late child actor River Phoenix, Joaquin was nominated for two Academy Awards. His musical talents were most famously showcased while playing musician Johnny Cash in 'Walk the Line.'

Actors Who Rock

    KIRSTEN DUNST, known for dating musicians, is now making some music of her own. The actress is writing a musical she's been working on for a few years.

    Soul Brother/FilmMagic, Getty

    JESSICA BIEL recorded vocals for the soundtrack of her movie 'Easy Virtue'.

    Matt Carr, Getty Images

    Steve Spatafore, Getty Images

    KEVIN COSTNER has a six-piece rock group called the Kevin Costner Band.

    Frederick M. Brown, Getty Images

    Actress KIM KARDASHIAN told E! in Sept. 2008 that she'd "be down" to make an album "if it was something fun. I love music, so it would just have to be the right thing."

    Bryan Bedder, Getty Images

    'House' actor HUGH LAURIE also plays piano and calls himself a "frustrated musician." He has also composed and recorded numerous original songs.

    Gregg DeGuire, WireImage

    The actor collaborated with Jim Brickman on the soundtrack of 'Cinderella' and released his debut album, 'A Long Time Coming,' in Sept. 2008.

    Lisa Lake, WireImage

    SCARLETT JOHANSSON's album of Tom Waits was released in May of 2008. She debuted her pipes on stage with Jesus and Mary Chain at Coachella 2007.

    John Shearer, WireImage

    Actor JOAQUIN PHOENIX, who portrayed Johnny Cash in 'Walk the Line,' is recording an album with Charlatans singer Tim Burgess. (Photo by E. Charbonneau, WireImage)

    MICHAEL CERA -- Impressed with his vocals and guitar skills in 'Juno'? Makes sense as he's had practice in his band, The Long Goodbye.(Photo ny Doane Gregory, Fox Searchlight)

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