Jessica Chastain

Jessica Chastain

Jessica Chastain researched Osama bin Laden extensively for new role.

The actress read "book upon book" to prepare for her role in controversial new film 'Zero Dark Thirty', Oscar-winning director Kathryn Bigelow's movie about the covert operation to kill the al-Quaeda founder.

The actress plays CIA agent Jen, who had a crucial role in tracking bin Laden to a compound in Abottabad, Pakistan, where he was killed on May 2nd, 2011.

Jessica said: "We did extensive research. Books upon books. I read [Lawrence Wright's] 'The Looming Towers', I read Michael Scheuer's book on Osama bin Laden. I got to know my subject inside out."

The film has been shrouded in secrecy, with those involved - including the film's stars, director and writer Mark Boal - reluctant to give away too many details. Jessica says this is because of contributions from real people involved in the operation.

She told GQ magazine: "I did talk to a lot of people but I don't really want to specify to whom I spoke.

"The reason they're trying to keep so much of it a secret is because there are so many people involved - real lives."