Call it \"Rocky on steroids\" if you like, but Warrior is a film with its testosterone levels set through the roof. We\'re talking not boxing but mixed martial arts (MMA), a full-on contact sport that blends a host of traditional fighting techniques, from wrestling to ju-jitsu. Put that with two of the most exciting actors of their generation, British-born Tom Hardy (Inception) and Australia\'s Joel Edgerton (Animal Kingdom), and the result is an explosive fight film that pulls no punches. We meet in London\'s Soho Hotel, where Edgerton and Hardy are sitting together on a grey sofa - about the only thing soft in this room. Bulked up to 84kg for his role as Bane in the forthcoming Batman release, The Dark Knight Rises, Hardy\'s long-sleeved grey sweatshirt looks as though it is about to rip under the strain of his muscular frame. Dressed in a denim cap and jacket, Edgerton may not quite be as Hulk-like, but given that he earned a black belt in Shotokan karate in his teens, you wouldn\'t want to tangle. Playing estranged brothers who both enter Sparta, a winner-takes-all MMA elimination tournament, these boys spent two months training in Pittsburgh - eight hours a day in the gym, learning boxing, weightlifting and ju-jitsu. \"It felt good to be strong,\" says Edgerton, 37, who added 9kg of pure muscle. \"And it felt good to learn something new. I certainly felt, by the time we were in the cage, standing there with a pair of gloves on, that you felt … at least part of you belonged.\" Not that a sense of \"belonging\" resonates much with their characters, particularly Hardy\'s Tommy. An ex-Marine and former wrestling prodigy, he returns from a tour of duty in Iraq weighed down by emotional demons, in particular his feelings towards his abusive, alcoholic father (Nick Nolte) and his brother Brendan (Edgerton), a former street brawler turned teacher who he believes abandoned him. \"The fight is within Tommy,\" says Hardy. \"He\'s fighting for country and for self, for reasons towards his own self-centredness and pain.\" Factor in Brendan\'s \"financial reasons\" for entering Sparta - he\'s desperate for money to support his family - and the pain in Warrior is not just physical. \"These are normal people in extreme circumstances with the backdrop of MMA,\" says Hardy, who gives the director Gavin O\'Connor (Pride and Glory) the credit for ensuring the drama is not just in the ring. \"When you ask, what does Warrior do for the MMA world where others have failed, it\'s talking about it as a sport as opposed to making a kung fu movie or a martial arts movie. It\'s like Rocky meets Kramer vs Kramer, if you like.\" Still, with real-life MMA fighter Greg Jackson on board as technical adviser, Hardy and Edgerton felt duty-bound to represent accurately a sport often maligned for its violence. \"It\'s no more brutal than a game of rugby,\" argues Hardy. \"If you go on to the pitch with the All Blacks, you\'d know about it. And that\'s 90 minutes. These guys do 25 minutes, one on one.\" Edgerton chips in: \"Boxing allows you to keep engaging in the fight, even if you start to lose brain cells. With mixed martial arts, the moment you can no longer defend yourself, there is a clear winner.\" Thrown into the cage with all manner of MMA fighters (many of whom appear in the film), Hardy, 33, even found himself facing off with Hans Marrero, one of whose sparring partners is the former heavyweight boxing champion Mike Tyson. \"I had a moment where I was like \'I really don\'t want to be here!\' I was standing there in my gloves and my shorts, and I was like \'This is really not for me!\'\" Edgerton concurs. \"Any of those guys would probably have me seeing stars within about 20 seconds.\" Get ready to rumble, as they say.