Dakota Fanning and Kristen Stewart have made three films together — from "New Moon" to their rocking girl-power flick "The Runaways" and then back to "The Twilight Saga" for "Eclipse" — and shooting the string of movies took some adjusting on their part. The three flicks have very different tones. Plus, Stewart and Fanning are mortal enemies in "Twilight" but best friends in "The Runaways."

"It's really funny, 'cause we did 'New Moon' before ['The Runaways'], and ... we got so used to seeing each other like Joan [Jett played by Stewart] and Cherie [Currie played by Fanning] in those costumes," Fanning said. "Her hair was short, and I had the wig on. And [then we] did 'Eclipse.' "

While having to remember if they hated or loved each other on set was one of the difficulties, Stewart said Fanning had another big problem: "She hated when I cut my hair."

Fanning got really upset when Stewart lost her long locks for Jett's short, spiky cut. "I think Dakota was more emotional than I was, to be honest," Stewart recalled. "She, like, almost cried when I cut my hair. It was something I needed to do. I needed to feel the sweat coming down my face and, like, I needed to be able to touch it. I just needed to do it."

Fanning remembers the day vividly. "I almost cried. And then we did 'Eclipse' after, and it was so weird being on that set and saying, like, different things to each other. It took me a little bit. It took me a take or two to get used to it."

Check out everything we've got on "The Twilight Saga: Eclipse" and "The Runaways."

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