PARK CITY — Kristen Stewart had three weeks to switch gears from acting as the lovesick, vulnerable Bella Swan in "New Moon" to Joan Jett, the tough rocker chick she plays in the Sundance film "The Runaways."
But the actress said she didn't give the drastic character change too much thought, and even discovered a softer side to the indestructible Jett.
Despite her reputation as the hardened frontwoman of The Runaways, a pioneering all-girl teenage rock band that gained fame in the '70s, Jett is "really sweet," Stewart said.
"She's very righteous. … I know that sounds weird — but she is the way she is because she stands up for what she thinks is right."
After meeting the real Joan Jett and Jett's former bandmate Cherie Currie, Stewart said the story became more personal to her and she had more appreciation for the possibilities for girls nowadays.
"The Runaways" follows the struggle of Jett and Currie as they fight against the odds of their time to find success in a male-dominated rock music scene.
"If nobody ever told her (Jett) to sit down and shut up, she might not be the way she is today," Stewart said.
Neither of the actresses, both born in the '90s, knew much about The Runaways before preparing for their roles in the film.
But they took a crash course on the band, with Stewart and Dakota Fanning learning vocals for some of The Runaways' biggest hits, including "Cherry Bomb," and Stewart learning the guitar chords for six other songs from Joan Jett herself.
As for a future singing career, Fanning said she can't imagine ever taking the microphone as herself, but could see herself taking on other singing/acting roles in the future.
The 15-year-old star said she took on the role of Currie because she was fascinated by the story and wanted The Runaways brought to the attention of an audience that might otherwise never know about them.
Playing a hard rock chick known as the sex kitten of the band, Fanning said there are some parts of Currie's life she will never understand, but other aspects are more familiar.
"I can understand being 15 and not knowing who you are yet and trying to figure it out while in the middle of this rock and roll scene," Fanning said.
With newfound appreciation for the legendary Southern California group, Fanning said the most significant thing she learned during filming was the realization that there was once a time when being in a rock band was "not the norm" for girls.
"I don't think there will ever be another band like The Runaways," Fanning said. "All girl bands don't have the same struggle that they had."