When it came to Warrior, however, and the part of promoter JJ Riley, O'Connor knew it was right to make an exception, although it's one he wishes he didn't have to make.
"The part was supposed to be played by Charles 'Mask' Lewis," O'Connor said. "I wrote the part for Charles. Charles was a really dear friend of mine. He opened up a lot of doors in the world of mixed martial arts for me. Through all my research, he and I became very close. We wrote the part for him. The promoter was Mask. He was written as Mask."
That changed when the TapouT co-founder died tragically in a March 2009 car accident.
"Just as I was starting to shoot the movie," O'Connor said, "Charles was killed, and a lot of his friends and my friends kept saying, 'Dude you should just play it,' do it in honor of Mask."
Stepping into the UFC Hall of Famer's shoes required some changes in the part – "Obviously I wasn't going to play Mask," O'Connor said, "so we changed it to a hedge-fund guy" – but as he looks ahead to the film's September 9 release, O'Connor can feel his late friend's influence throughout the film.
"I felt Charles' presence every day with me," O'Connor said of the filmmaking process. "I felt he was on my shoulder, whether I was playing the part that was intended for him or just every day making this movie - cutting the movie, through all the post-production, everything – to this day, I feel like Charles was an angel, watching over the process. We had so many obstacles, and we got through all of them. We truly believe that Charles was sort of holding our hands and pulling us through. His presence was felt every day."
Speaking with O'Connor – who was also the executive producer of The Smashing Machine, a 2002 documentary about Mark Kerr – it quickly becomes clear that he shares a certain reverence for the sport with his late friend.
"There was one moment a couple of years ago that really hit home for me for my appreciation of the spirituality and respect of the sport," O'Connor said. "I remember when GSP fought Jon Fitch in a five-round war. When it was over, they both got on their knees in the middle of the cage and bowed to each other. I just remember watching that and going, 'Man, if that doesn't epitomize the beauty and represent what the sport is all about, I don't know what does."
While that moment encounter between GSP and Fitch was influential on O'Connor during the process of writing, directing and acting in Warrior, he was reluctant to put the UFC Welterweight Champion in the movie, although other fighters appear, including Yves Edwards, Nate Marquardt and Anthony "Rumble" Johnson.
"I didn't want anybody who was too famous," O'Connor said. "Someone suggested bringing Georges St-Pierre in, and I thought he was too famous."
The SPARTA promotion that serves as the backdrop for the film isn't intended to be a stand-in for the UFC, as it utilizes the one-night tournament format that the UFC hasn't used since 1999. According to O'Connor, the format was necessary to set up the final conflict between brothers Tommy Conlon (Tom Hardy) and Brendan Conlon (Joel Edgerton).
"There are a lot of reasons why I did it," O'Connor said. "Number one, I needed this bracket sort of thing, whether the brothers are on a collision course to fight each other. We could have done it over the course of a year, but that, dramatically, wouldn't have worked. Also, I loved those grand prix tournaments from PRIDE, and in Brazil. I'm making the movie, and I wanted to do something that you don't see. I love the UFC, and I think I'm very reverential to the UFC in the movie, but I didn't want my tournament to look like the UFC."
While he may not have patterned his movie's MMA promotion after the UFC, O'Connor hopes that his film will inspire greater interest in the UFC and the sport as a whole, and his experiences while screening the film have given him cause to expect that.
"I've been meeting so many people that have never seen an MMA fight, have no interest in the sport, or have a preconception of what the sport is," O'Connor said. "When they leave the movie, they say to me, 'I'm really interested in this sport now. It's not what I thought it was.' That, to me, is a great thing. It is a love letter to the sport. People can see this movie that have no idea about the sport, or have preconceptions about the sport, and then walk away from the movie having a different perspective on the beauty and the art form and the athleticism."
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