Pitt and writer-director-producer Rachel Boynton screened the oil doc, which premiered at the Tribeca Film Festival last year, to a small audience at Sundance Sunset Cinema.
It took Boynton about six years to make the film. She spent a year and a half traveling to West Africa before even beginning shooting.
"There were multiple crews that were arrested and deported from Nigeria -- foreign film crews -- while we were shooting and I believe ours was the only one that was not arrested and deported, which is something I'm proud of," Boynton said. "But that's in large part due to the relationships that I developed over the year and a half that I was traveling back and forth."
Pitt and his Plan B production company got on board when the pic was still focused on Nigeria. Boynton later shifted gears when Texas-based oil startup Kosmos Energy allowed her to follow its journey to pumping "first oil" from an offshore oil site (Jubilee Field) they discovered in Ghana.
Pitt joked that he could have shot 12 films in the time it took to make the documentary.
"It's this staggering endeavor to me to stick with the subject this long and follow it so deep. It takes time to devolve that kind of elegance and structure to tell this story and to assign no side to it and let the people stand for themselves. I think it's an incredible feat," he said.
After her second trip to Nigeria, Boynton came to the conclusion that she needed backing from someone like Pitt if she wanted to get the film off the ground.
"I realized that nobody knew who I was and nobody was going to take me seriously unless I had somebody believe in me, like Brad," she said. "I think the support of Plan B made a huge difference in terms of getting the film made because it made people take me seriously as a filmmaker."
Pitt said he's "dying to see" more investigative reporting of this caliber that doesn't draw distinct boundaries between heroes and villains.
"We're always looking, certainly from Hollywood, (for) this idea of good guys and bad guys," he said. "We're also dealing in a media that's more focused on sound bites and a sensational headline. This is the complete antithesis of that and what we need more of, and it comes from a curious mind investigating a complex subject."
Boynton also gained unprecedented access to a Nigerian militant group called the Deadly Underdogs, most of whom were thrilled by the idea of appearing in a movie.
"The film is called 'Big Men' for a reason and the tag line is 'everyone wants to be big,'" she said. "The basic idea in the movie is that being big has to do with getting a lot of money or getting a very big reputation. Nobody was making money off of this film, but the notion of reputation is very important. People choose to be in movies in general because they want to be heard."
For Pitt, having a voice in Hollywood also comes with responsibility.
"You need to have world experience to know what you're speaking about; sometimes we're too quick to speak without having done all the research," Pitt said. "We get to sit in a seat now where I can give some assistance -- very little in this case -- to projects that I think are worthwhile. They speak to our time, speak to us as human beings and point us in a better direction."
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