Fanning, left, on Monday night in Los Angeles as a brunette (Photo: Steve Granitz/David M. Benett/WireImage)Dakota Fanning showed her dark side on Monday night at the world premiere of "The Twilight Saga: Breaking Dawn - Part 2" in Los Angeles.
Going from blonde to brunette, Fanning was looking more like Francis Bean Cobain (or even Zooey Deschanel) than herself. But, she reassured Yahoo! Movies, "Yes, it's really me." The 18-year-old said the dark hair color was for a movie she just filmed. "I decided I needed a change... for the character I was playing I couldn't be a blonde."
Watch Dakota Fanning at "Twilight: Breaking Dawn - Part 2" premiere:
Change is good: Fanning stunned in an Elie Saab emerald green dress with a sparkling sheer asymmetrical midriff panel. And she confirmed that the "dress choice was totally dependent on my hair color."
Fanning was there to celebrate her "Twilight" character, Jane, and so were fans, which had her leading by far in the Yahoo! Movies Ultimate "Twilight" Fan Poll in the most evil vampire , even beating out Aro (Michael Sheen) whose character heads the Volturi.
The star noted about the role, "It's nice to let go, and know that your character is mean, and just have fun with it." She added, sometimes, "It's good to be bad."
[Yahoo! Movies Photos: 'Breaking Dawn - Part 2' world premiere social media highlights]
Get a full look at Dakota Fanning's "Twilight" premiere dress:
No mean girl tonight. Fanning only had kind words for the fans: She told them, "Thank you so much to everyone. I'm a fan myself. I'm excited to be here."
Maybe Dakota's biggest fan, little sister Elle Fanning, joined her older sibling at the premiere to give her support, wearing head-to-toe Prada. The cute and stylish outfit was paired with wild platform sandals, sort of gladiator meets Barbarella, which almost stole the show. And Elle's hair -- still very, very blonde.
Elle Fanning on Monday night in Los Angeles (Photo: Jason Merritt/Getty Images, Steve Granitz/WireImage)