A fourth Jason Bourne film seems even more of a certainty after a screenwriter was signed to pen the next flick in the franchise.

Oscar-winner Matt Damon has played the amnesiac secret agent on three occasions, starring in Doug Liman's The Bourne Identity before British director Paul Greengrass took the reins for the two sequels.

And according to trade newspaper Variety, George Nolfi - who wrote the script for The Bourne Ultimatum - has been signed by Universal Studios to concoct a fourth film.

Greengrass and Damon are both already contracted to the new project, though the pair's latest collaboration Green Zone is their current concern.

The hugely successful trilogy of Bourne movies were based on books by the late Robert Ludlum but the fourth will be an entirely original story.

Plans for a new Bourne film emerged in February when Variety claimed Universal had signed Greengrass and Damon to shoot another picture about the assassin.

Speaking at last year's Cannes Film Festival, Damon had said he was "definitely done" with playing Bourne adding: "I think we've ridden that horse as far as we can.

"The character lives on in the books and if someone else wanted to play it, I guess they could."

But while Ludlum only penned three Jason Bourne books, both Damon and Greengrass later said they would consider making a fourth film as long as the other was involved.

17/10/2008 14:23:32