"There's something a little off about her and there's still something off about me, so it seemed like a good match," the Mirror quoted her as telling the US.
The actress gets to put her stunt skills to the test in the film, playing an agent on the run after being labelled a Russian sleeper spy. "There was a real duplicity to her personality and there's a part of her that's not necessarily a good guy - because of certain things that happen to her she's a bit damaged," she explained.
But, in real life, Angie admits she can't imagine keeping any secrets from her partner Brad Pitt and their six children.
"For me, the most interesting thing if you work with the CIA is that you can't share anything about your work or your life with your family or your friends, so you become this very lonely, isolated, miserable person that has a lot of secrets. It's a very unusual specific type of person that would do that and it's a very big sacrifice that these people make," she added.