Joaquin Phoenix 'pretending' to have a nervous breakdown

Joaquin Phoenix is "pretending" to have a nervous breakdown.

The star - who is filming a documentary about his transition from acting to hip-hop music - is apparently faking his recent public outbursts for the film, directed by 'Gone Baby Gone' actor Casey Affleck.

A source told Entertainment Weekly magazine: "He said, 'It's a put-on. I'm going to pretend to have a meltdown and change careers, and Casey is going to film it.'

"It's an art project for him. He's going full out. He probably has told his reps that he's quit acting. Joaquin is very smart.

"This is very conscious. He has a huge degree of control."

The stunt is said to be a satire on stars who take themselves too seriously. Joaquin's recent performance at LAVO nightclub in Las Vegas reportedly saw him "storm out" after losing his cool with a film crew.

A source said: "He was waiting for Casey and when the film crew arrived late, Joaquin flipped out. Phoenix yelled at the crew, 'Thanks for being late and f***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. Nobody can tell if he is for real or if this is all a big joke."

The star has also leapt on stage during a Jamie Foxx concert and started grinding up against him before stealing a woman's hair clip and wearing it.