EXCLUSIVE: Jake Gyllenhaal Reveals the Hardest Part of Playing Boston Marathon Bombing Survivor in 'Stronger'

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Jake Gyllenhaal took his latest role very seriously -- maybe even too seriously. 

The 36-year-old actor stars as Jeff Bauman, a Boston Marathon bombing survivor who lost both his legs, in Stronger, but told ET that the hardest part about playing Bauman was finding his "humor."

"I think just sometimes understanding his sense of humor in the midst of, like, pretty dark things, that was hard for me," Gyllenhaal revealed to ET's Cameron Mathison at the Toronto Film Festival last week. "Because I think I I sometimes take situations too seriously and I think his sense of humor, how crude it is in the face of situations where you never expect it." 

Stronger, based off of Bauman's memoir of the same name, forced Gyllenhaal to learn to understand Bauman's pain as he adjusted to his new life after the bombing, and the actor says channeling Bauman's struggles helped him learn about himself.

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"What he made me realize is that inside of us all is a superhero," Gyllenhaal shared. "Inside of us, in the darkest times, in times where we feel like people we love that were close to us are struggling and we won't make it through another day, or another hour, a minute, or a second, there is that thing inside of us, and Jeff shows us that every day."

"Playing a character like that in a film was an opportunity for me to learn that about myself and see my own faults and see my own weaknesses, but also, as Jeff reminds me every day, see my own strengths in places that I never thought I could be strong," he added. 

"It's hard to see that when you're going through it," Bauman shared with ET. "It's really hard to see that you could always bounce back from a loss." 

The message of bouncing back is something Gyllenhaal hopes viewers take away from the film. 

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"Around the world, with all these [hurricanes] and then also just some of these horrible things that are happening, know that you can end up in an even better place than you began," he said. "In my moments of darkness, where you think you can't continue, you can and most likely you can get to an even better place than where you started." 

"That's what Jeff shows us, and it's an incredible story," Gyllenhaal added.

Stronger, also staring Tatiana Maslany, Miranda Richardson and Clancy Brown, hits theaters on Friday.