Joan Jett and her creative and business partner Kenny Laguna are expressing optimism for "The Runaways," the film based on the maligned but influential all-female rock band that Jett co-founded and led from 1975-79.

The film, which is partly based on Runaways singer Cherie Currie's 1989 memoir "Neon Angel," features "Twilight" star Kristen Stewart as Jett, Dakota Fanning as Currie and Michael Shannon as original producer Kim Fowley. It was directed by Floria Sigismondi and is currently in post-production, with a release planned for 2010.

"It was very surreal and hard to put a word on," Jett, who executive produced the film and was on hand for the filming, tells Billboard.com. "If anything it definitely made me smile. It reinforces my love for the band and the fact I think it was an extremely important band, regardless of our level of success in America. It just reinforces my love of the whole time and of the band and what we did and how it was implausible and improbable at the same time."

And Jett hastens to explain that "The Runaways" is "absolutely not a biopic. It's not fact-for-fact. What they did was basically take elements from the Runaways story and created a parallel narrative."

Laguna adds that, "We're hoping it will be great. They exceeded our expectations with the casting...Even if it's not a huge movie, it's going to have a colossal effect on young girls playing rock 'n' roll, for sure."

Jett and Currie each coached their cinematic counterparts during the filming, and Jett was particularly impressed by Stewart, who came to the set almost immediately after wrapping the second "Twilight" film, "New Moon."

"Kristen was so into it, into the whole vibe of doing this," Jett reports. "I think she felt a weight and a responsibility to interpret it correctly. She was really serious about it and was watching me and asking me all sorts of question, from speech aspects to watching my body language, watching where I stood, watching my guitar playing. She really worked hard to get it right."

The Runaways were previously the subject of a 2004 documentary "Edgeplay: A Film About the Runaways."

Soundtrack details are currently being worked out for "The Runaways." Jett, meanwhile, is considering releasing a new greatest hits album in 2010 that may include some of the new material she's been working on.