Joan Jett: 'Stewart did an amazing job'

Joan Jett has praised Kristen Stewart for her work on The Runaways.

Jett, who is played by Stewart in the movie, explained that she was "impressed" by the actress and her co-star Dakota Fanning.

"I think Kristen - well, both of them really - did an amazing job," she told Us Weekly.

Jett added that she tried to help Stewart with the role by giving her as much information as possible.

"When we first met, I talked and talked and talked at her for hours," she explained. "About The Runaways, and told her stories I'd never told anyone else. I thought it was important. I gave her tape of me talking at 14 so she could hear the way I was."

Jett continued: "I wanted her to know Joan and not Joan Jett. You get so used to the hair and the makeup and the leather jacket as opposed to the person behind that and I wanted her to know the person. I think we really did get down to that."

Stewart has recently admitted that she was anxious about portraying Jett properly.