The two thespians were tested to the full when it came to giving chase in the new film - because no matter how hard they tried they struggled to look convincing.
Parker explains, "Helen and I both said that we thought as soon as they saw us run that we'd both be fired. It takes a certain kind of commitment to run and look like there's a lot of drama happening around you and then to fall.
"I don't mind being pulled to the ground if something was blowing up but it takes something entirely different to fall and roll down a hill. That's challenging for me. I'd rather do a six-page monologue than roll down a hill. It's really not in my skill set.
"Helen felt the same way and there were a couple of times when we were both laughing and saying, 'OK, here's our running scene.' She's like, 'Not only am I running but I'm running with a gun!'"