According to The Insider, the film has the working titles Killing Hasselhoff and Celebrity Death Pool. Australian comedian Jim Jefferies confirmed The Bieb's appearance in the movie to the entertainment show. If it's any consolation The Insider also spoke to comedian Ken Jeong, and he at least hinted that Bieber might only be in one scene.
According to Hasselhoff, he convinced Bieber to appear in the movie because the young singer owed The Hoff a favor. However, given Bieber's allegedly checkered past with cars, he's certainly a unique choice for the role. Check out the video at The Insider for more shots of the two of them during filming.