Casey Affleck, the younger brother of Ben Affleck, has made a mock documentary about Joaquin Phoenix starting a career in rap music.

Affleck, director of the project, is said to have completed making the mockumentary- featuring his brother in-law, Phoenix, going through the ropes of getting on the rap music ladder.

They are now seeking a buyer for it.

Rumors circulating the movie world say that the pair held a screening for the mockumentary in Hollywood last week.

Harvey Weinstein is supposed to have attended.

Phoenix has always been a bit peculiar to say the least but it was his appearance on "Late Show With David Letterman" that pulled out all the stops last year.

Phoenix arrived on the Letterman stage with a scraggy beard and for most of his interview he mumbled and grumbled.

Rumors were that he was drunk but who knows.

Letterman even said to him "I'm sorry you couldn't be here tonight."

Apparently the film will divulge whether or not Phoenix was serious about quiting his acting career last year.

However, much of the details of the film are a secret.

How does Phoenix go from being an Oscar-nominated actor to an aspiring rapper?

I guess we'll never know unless Affleck gets a buyer for the movie.

Casey Affleck: Director of Joaquin Phoenix mock documentary