In the action drama Alex Cross, Matthew Fox plays a psychopathic serial killer obsessed with inflicting pain on his victims.
But the actor found himself on the receiving end during the shoot when co-star Tyler Perry almost knocked him unconscious.
''He's a big guy and he threw an elbow that caught me right in the jaw and it hurt,'' the 46-year-old former star of Lost confesses. ''But that's part of the deal and I've been on the other end of that, when I accidentally hit a stunt guy on the film Speed Racer, so I told him, 'It's no worries, man, I'm not really hurt so let's get on with it!'''
Perry, 43, is best known as writer, director and star in drag of the hugely popular ''Madea'' movies. Alex Cross marks his first big action role and he looks horrified as he gives his version of the mishap on set. ''He was the enemy on-screen so we never talked before making the movie,'' Perry says. ''Then we had a fight on a catwalk and suddenly I've almost knocked him off the catwalk and I'm holding him because he's about to fall and he says, 'What happened?' - so that was our introduction!''
Alex Cross is inspired by the James Patterson series of best-selling novels about Detroit homicide detective Alex Cross (Perry), who was featured in two previous films - Along Came a Spider and Kiss the Girls - played by Morgan Freeman. The reboot shows the origins of the character, when he is caught up in a hunt for a serial killer nicknamed Picasso (Fox).
Fox is almost unrecognisable in the role after six years playing the heroic Jack Shephard in Lost. He proudly admits he lost almost 18 kilograms to inhabit the tattooed body and warped mindset of Picasso, but that his research began long before the role. ''Throughout my life, any time a documentary came on about Ted Bundy or Jeffrey Dahmer or other serial killers … I've always been fascinated by them and trying to figure out what kind of thought process someone has to build in themselves to justify those kind of obsessions,'' he says.
When Lost wrapped in 2010, Fox, his wife and two children, aged 10 and 15, moved to a cattle ranch outside a small town in Oregon. He avoids Hollywood, but seems at peace with his place in it for now.
''A lot of people watched Lost, so it's understandable they're going to identify me as that guy,'' he shrugs. ''But I have three films coming out in the next eight months so I'd like to think if I stay in this business and do more films, people won't be saying that in five years.''
GENRE Action drama.
CRITICAL BUZZ Lukewarm US box-office and poor reviews.
STARS Tyler Perry, Matthew Fox, Edward Burns.
DIRECTOR Rob Cohen.
RELEASE Now screening.