Neil told ABC News Radio in an exclusive interview that the 63-year-old actor will make a cameo appearance as Osbourne in the film.
"How funny is that going to be," Neil told ABC's Al Mancini at the opening of Vince Neil Ink, the singer's new tattoo parlor in Las Vegas.
"The Dirt: Confessions of the World's Most Notorious Rock Band" was a 448-page tell all confessional, cataloguing the drug and alcohol abuse, nasty infighting and sex parties of Neil and band mates Tommy Lee, Mick Mars and Nikki Sixx.
The film is in pre-production and will be released in 2008 by Paramount and MTV.
But, unknowns will play all the Motley Crue, ABC said.