"Walk the Line" star Joaquin Phoenix isn't off to a great start with his new career. The actor-turned-rapper threw a fit before performing at Lavo in Las Vegas Friday night.
"He was waiting for Casey Affleck" — who's directing a documentary about Phoenix's venture - "and when the film crew arrived late, Joaquin flipped out," said our insider.
The spy said Phoenix yelled at the crew, "Thanks for being late and [bleep]ing everything up."
He then threw a CD on the floor and stormed out.
"He came back five minutes later and did the sound check," said the source, who added, "Nobody can tell if he is for real or if this is all a big joke."