Will Smith has starred in many memorable movies and he’s about to add to that list with his latest film, “Concussion,” where he plays forensic pathologist Dr. Bennet Omalu, who discovered a connection between football injuries and brain damage.

Smith has earned a Golden Globe nomination for the role, but admits he was “conflicted” about originally signing on to the project.

“It’s going well. I was a little conflicted when I first took this film, so it feels good that people are responding well to it,” the actor said on “Good Morning America” today.

The movie chronicles Omalu’s discovery of CTE, or "chronic traumatic encephalopathy," a degenerative brain disease caused by repeated blows to the head that multiple NFL players have been diagnosed with after their deaths. Smith calls the discovery a “very inconvenient truth.”

His son, Trey, played football for years.

“My son played for four years and it was some of the most beautiful time that we’ve had together,” Smith, 47, said. “This is not an anti-football movie. I love football, I grew up in Philly. I’m a football fan, my Eagles. It was a very inconvenient truth.

“The reality of the science, and as a parent I knew that I didn’t know when my son was playing football, I didn’t know that repetitive head trauma from the game could cause long-term brain injury. You can make any decision that you want, but for me, as a parent, I was compelled to deliver this film to the world.”

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The NFL has told ABC News it has made a number of changes to the game to “enhance the health and safety of players at all levels of football” and that it is “seeing measurable results, including a 34 percent decrease in concussions in NFL games since the 2012 season.”

Playing the role of a real-life character, an American immigrant who took on one of the most powerful institutions in the world to fight for what he believes is the truth, required an added responsibility for Smith.

“There’s a little more weight to it, specifically with ‘Concussion,’” he explained. “We shot it in Pittsburgh so the families of a lot of the players were on the set. Some of the locations we used were the actual places that these things happened. There’s an added burden and responsibility to the fact that these are people’s lives that you’re actually going to see and they’re going to watch the movie.”

As Smith was preparing for the role he shadowed Omalu while he was performing several brain autopsies.

“I saw him perform four autopsies. Because you know I take my work seriously. I’m committed,” he said. “I went in there with him, and autopsy is aggressive. But I went and I watched him, and he sees himself as a deliverer of souls. He’s playing music. He’s talking to the person and he sort of sees himself as delivering the soul from this world to the next. As an actor, I was just ecstatic to find that depth of an interesting character.

“He is such a beautiful man. He’s just sweet and brilliant,” Smith added. “He has eight degrees. He’s a man of science but paradoxically he’s a deeply spiritual man. He blends those two things, the science and spirituality into one gorgeous being.”