Mark Strong has been talking about how the first script for Zero Dark Thirty had to be "scrapped and started again" after Osama bin Laden was captured and killed.
"The original was about the failure to catch Osama when he was in the Tora Bora caves.
"After it all happened the CIA let the director Kathryn Bigalow and writer Mark Boal have access to some of the information about the hunt," Mark said
"I must say it was great being part of a story written by a journalist rather than, you know, Hollywood glamour people," the actor added.
The movie also stars Jessica Chastain as the lead character Maya.
Zero Dark Thirty is released in the UK on January 25.