The Mr. and Mrs. Smith star originally signed on to front the film in 2011, but he has since dropped out and moviemakers are now considering switching the gender of the lead character.

The Gray Man will be based on Mark Greaney's 2009 novel about a Central Intelligence Agency employee who becomes a hitman in a bid to save his daughters.

James Gray and screenwriters Joe and Anthony Russo were attached to helm the film, but moviemakers are still searching for a new director.

If Theron signs on to the film, she will not be the first woman to step into a role originally intended for a man - in 2010, Pitt's wife Angelina Jolie took over the lead role in Salt after Tom Cruise dropped out.

Sandra Bullock also recently starred in Our Brand is Crisis after convincing producers to change the lead character from male to female, so she could tackle the role originally considered a vehicle for her Gravity co-star George Clooney.