The actress plays Central Intelligence Agency operative Carrie Mathison in the hit TV show and she reveals the character is based on a real woman who works for the covert agency.

Danes, who refuses to name the agent, was able to meet her at the CIA headquarters in Virginia and see what goes on behind the scenes at the highly secretive organisation.

She tells Britain's S magazine, ""Obviously I can't say who it is, but I met her and she took me to CIA headquarters. She introduced me to her colleagues, including the man who was the head of the Pakistani division and had just returned to the U.S. after the killing of Osama bin Laden. I was like, 'Wow! This stuff really exists.' But they were surprisingly forthcoming.""