Justin Bieber will voice the iconic Kitt car used in David Hasselhoff's 1980s Tv series Knight Rider for the actor's upcoming comedy.

The Baby hitmaker was pictured filming scenes inside the classic vehicle with the former Baywatch actor earlier this week (begs22Sep14) and a star of the film, comedian Jim Jefferies, has confirmed Bieber will be the voice of the indestructible Pontiac Firebird Trans Am, replacing the original voice of William Daniels.

Jefferies tells The Insider with Yahoo!, "Justin Bieber is the voice of Kitt in this movie - you can't say that every day."

Hasselhoff adds, "He (Bieber) called me and asked me for a favour. I called him back and said, 'As a friend, could you do me a favour'. And he said, 'Yes'. And you know what? I did his favour first because I love the Bieb. I think he's a cool kid, and he gets a bad rap. He's a good guy, and I like his music. I've known him for five years, since the European Music Awards. I called him and said, 'Would you do me a favour?' And he said, 'Yes'."

Bieber has appeared in a number of films as himself and he played a teenage serial killer in two episodes of Csi: Crime Scene Investigation in 2010 and 2011.

The comedy, currently titled Killing Hasselhoff, is about a man who tries to win a bet by hiring an assassin to kill the actor.