Downey Jr. to star as playboy Hefner?

Robert Downey Jr. has been tipped to play legendary porn mogul Hugh Hefner in a big-screen biopic - after reportedly impressing the Playboy entrepreneur with his lead role in 'Iron Man'.

Veteran lothario Hefner was so pleased with the former hellraiser's portrayal of wealthy playboy Tony Stark in this year's comic blockbuster, he is desperate to sign him up for the role.