Actress Jessica Chastain has been banned from talking about her top secret new movie Zero Dark Thirty after accidentally spilling film details to an undercover journalist.

The upcoming action thriller chronicles the real-life decade-long search for terrorist leader Osama bin Laden, who was tracked down and killed by a Navy SEAL team in Pakistan in May, 2011.

The script, penned by Mark Boal, has been kept tightly under wraps since the project is based on true events and issues concerning national security, but chatty Chastain admits she once said too much while at an industry party - and she was promptly scolded by producers.

She tells Marie Claire magazine, "I got into trouble once because at a party, I told someone I didn't know was a journalist that I was going to India (to film the movie). And then I got all these e-maills: 'Why did you say anything?!'"