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Katy Perry

LOS ANGELES, CA - JANUARY 27: Recording artists Katy Perry (L) and John Mayer pose backstage at "The Night That Changed America: A GRAMMY Salute To The Beatles" at the Los Angeles Convention Center on January 27, 2014 in Los Angeles, California. (Photo by Larry Busacca/Getty Images for NARAS)

What Were They Thinking?! (week of 1/27/2014)

This week's worst-dressed celebs include Katy Perry, John Mayer, and Pharrell (thanks to his now-infamous Vivienne Westwood hat)!

Wanna see the best-dressed? Check out our weekly 2 Hot 2 Handle gallery.