Michelle Trachtenberg's Blue HairDonato Sardella/WireImage; Justin Campbell/BuzzFoto.com

Michelle Trachtenberg’s hair now has bright blue ends, and it’s all because of her new role as a psycho killer in the thriller The Scribbler, out next year. “It wasn’t even something they asked me to do, I just said ‘I think half my head should be blue,’” she told us at the Coach-hosted Childrens Defense Fund benefit party in Santa Monica last night. While producers denied a full head of blue hair, they compromised with just the tips, and Trachtenberg sought celebrity colorist Tracy Cunningham to dip-dye her strands. “We did it and it’s been so much fun,” she said. Of course, it took some getting used to. “It is super subtle though during the day it is a bright,” she said. “But after the first washing, I thought I killed one of the characters from Avatar!” Tell us: Do you like her look?

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— Kwala Mandel