KStew & Fanning-BFFs

BEVERLY HILLS, California — By now, you know that Dakota Fanning has joined the "Twilight" franchise, as well as the upcoming punk-rock biopic "The Runaways."

But what will happen when the famous child star goes grown-up alongside Hollywood's fastest-rising A-lister? Well, Kristen Stewart hopes the duo will become close friends.

"I can't wait to actually work with her," the 18-year-old Stewart told us after hearing the Fanning news. "We aren't BFFs yet, but hopefully."

Stewart is a busy gal these days, with "The Cake Eaters" opening in limited release this week, "Adventureland" hitting theaters April 3 and "New Moon" pre-production kicking in for stars like herself, Fanning and Kellan Lutz.

"I'm so excited that she took the part in 'The Runaways,' " Stewart said of Fanning's plans to portray Cherie Currie, the hard-partying lead singer of the '70s all-girl punk band. KStew was cast a few months ago as the band's rhythm guitarist, Joan Jett.

"[We] have a short amount of time to do that in between the two other ['Twilight'] films, because we are shooting them back-to-back," Stewart said. "They shut down for, I think, eight weeks, in between 'New Moon' and 'Eclipse.' "

Stewart has spent the past few months preparing for the movie with the real-life rock icon she'll portray, and she can't wait to have Fanning join in on their jams. "I've been listening to [Jett's] music all the time; I spent New Year's with her, and I am just trying to make myself aware of the time period and what she was going through," Stewart said, adding that she's trying to convince director Floria Sigismondi that her guitar and singing skills are good enough to avoid lip-synching. "I really hope to perform the actual music, but I just don't know yet. Hopefully, I'll be able to tell you guys soon.

"It's one of the most immense responsibilities to play a real person. If it is not done right, it should be publicly acknowledged," she insisted, declaring her dedication to the 50-year-old Jett. "Her story is important. It is an incredibly triumphant feminist story, really. She is an incredibly distinct personality, and so many people love and admire her, and so many people know her as just being one of the coolest people ever to live — and that, in itself, has been one of the most intimidating things that I have ever had to confront."

Fanning will likely spend some similar time bonding with Cherie Currie, who joined the Runaways at age 15 and now makes a living in California as a chainsaw carving artist. "The main thing that [Jett] talked about was how much she cares about that period of her life," Stewart said of her time picking the "I Love Rock N' Roll" hitmaker's head. "That band, the Runaways, is what started her entire life. She is very happy that it's being told. ... She is the first woman to ever start her own record label, and she's just a good person. She's got ambition, she's got conviction, and she's just cool."

And now, Hollywood's fastest-rising female star and its best-known child star are getting ready to play cool together. "It's gonna be intense," Stewart grinned, thinking about doing consecutive movies with Fanning. "It's a big deal."