Kat joined Joan Rivers Kelly Osbourne Guiliana Rancic and George Kotsiopoulos on E!’s Fashion Police yesterday!

On the show where nothing is off-limits, it’s no surprise that everyone began talking about their derrieres and whose was biggest. Prompted by Giuliana Rancic, Kelly Osbourne and Kat Graham had the very first Fashion Police “butt off” with Joan Rivers acting as judge – and measuring each tush with her hands!