In the true drama Stronger, Jake Gyllenhaal plays Jeff Bauman, who lost his legs in the 2013 Boston Marathon bombing and became a symbol of hope for the city as he recuperated. The actor says that the story was so undeniable that he had to make the movie.

Jake Gyllenhaal stars in 'Stronger'Jake Gyllenhaal stars in 'Stronger'

"It was just so beautiful, tragic and so funny," he says. "It's a story of a human being working their way through the inexplicable. Jeff is a representation for every one of us, though we have not experienced that. I think the reason to make this film, and Jeff and I talked about this, is that when you're with him, you feel life. I think it's an incredibly important story to be told."

In working closely with Bauman, Gyllenhaal says he was challenged to let go of his cynicism. "I feel like, in art films or in a certain type of film that I gravitate towards, there's a sort of cynicism that I believe in," he says. "But I'm starting to explore something else too. Merging those two ideas was what this movie was for me: can you believe in the idea of a hero? Do you think that that idea can really exist in this space? Because movies have always told you it's like this or it's like that."

Watch the trailer for 'Stronger' here:

Gyllenhaal admits that it takes him awhile to find any character he plays. "It's just time," he laughs. "It's a lot of time! I've always needed a long runway. There are things that come, you're sort of immediately inspired, and you kind of go, 'OK, I can see where it is, but it's far off.'"

And for this film, he knew he would have to imagine being in Bauman's situation. "That's part of the fraudulent aspect of what we do in making movies," Gyllenhaal says. "As much as I spend time with Jeff, as much as I know him, as much as I learn about the situation, as much as I talk to everyone around him, there's no way. It's fraudulent. You're constantly reminded of that. But you're in that energy, you're thinking about that often."

More: Jake Gyllenhaal on his friendship with Jeff Bauman

Of course, for the actor this struggle is what makes the job so worthwhile. "Mimicry and that creation is what I have loved since I was a kid, and that's the thing I do it for," Gyllenhaal says. "I love observing, I love human behaviour. I love the oddities of it, the beauties of it."