Third 'Riddick' will be "lean"

The director of the next Riddick film has revealed that the third instalment of the franchise will be edgier than first sequel Chronicles.

David Twohy told fans via a short film on star Vin Diesel's Facebook page that he wants the movie to have the adult rating of original Pitch Black.

He said: "We want to maintain our R-rating. We are going to be lean, and we're going to do it quick."

Diesel added that he is "committed" to the third film being more appealing to an older audience.

The Chronicles of Riddick was given a PG-13 rating.