Stewart 'feeling pressure of Jett role'

Kristen Stewart has admitted that she feels anxious about her role in The Runaways.

Appearing on The Tonight Show With Jay Leno, Stewart explained that she wants to make sure that she portrays Joan Jett's mannerisms properly.

"You always feel the pressure," she said. "It's like, if I don't get every little thing right I'm going to kill myself.

"And we have very different tics. We're both, like, ridden with tics but they're a completely different set of them... She's got a hunch. But a cool one."

Jett has previously described the movie as "surreal", while Stewart's Twilight co-star Robert Pattinson claimed that it is "really good".