6 / 12

Demi Lovato

LOS ANGELES, CA - NOVEMBER 05: Recording artist Demi Lovato arrives at FOX's "The X Factor" Finalists Party at The Bazaar at the SLS Hotel Beverly Hills on November 5, 2012 in Los Angeles, California. (Photo by Jon Kopaloff/FilmMagic)

What Were They Thinking?!

This week's worst-dressed crew includes Mischa Barton, Beyonce, and Britney. -- By Matt Whitfield, Yahoo! Staff