Gerard Butler is in talks to star in 'Hunter Killer'.

The 'Machine Gun Preacher' actor has been approached to appear in the film - which is based on a novel, 'Firing Point', written by George Wallace and Don Keith - with Relativity Media also keen to get Sam Worthington on board.

The movie follows a rogue Russian general who kidnaps his country's president, who is pursued by an untested submarine captain - the role Gerard is in negotiations for - and a Navy Seal unit, which the 'Clash of the Titans' star in line to play the naval commander.

It is not yet known who would play the general or the Russian president.

Antoine Fuqua has already signed up to direct the movie, which is scheduled to begin shooting either later this year or early 2012.

It already has a release date in the US of December 21 next year.

As well as 'Hunter Killer', Gerard - who has just finished filming comedy 'Playing the Field' - also has surfing movie 'Of Men and Mavericks' coming up.

Meanwhile, Sam - who recently appeared in 'The Debt' and 'Last Night' - can next be seen in 'Man on a Ledge' and fantasy sequel 'Clash of the Titans 2'.