Jessica Chastain has revealed she threw herself into the role of a CIA analyst in Zero Dark Thirty with a little too much intensity.
The actress stars in Kathryn Bigelow's new film as Maya, who dedicates herself over period of years on the hunt for Osama Bin Laden.
But speaking at the movie's Los Angeles premiere, she confessed that Maya wasn't an easy character to embody.
"It was a dark time," she said. "I love all the characters I play but this one I was very happy to leave."
"I rehearsed this movie for three months before filming, we filmed for about four months and that's nothing compared to what Maya did," she explained.
"I tried to put myself in a situation where even when I finished working I'd come home and still be in it."
"I made copies of pictures of the terrorists and hung them in my hotel room so I would always be in that environment and always have that in my mind."
Zero Dark Thirty, written by the Oscar-winning writer of The Hurt Locker, Mark Boal, also stars Jason Clarke, Jennifer Ehle, Chris Pratt and Mark Strong.