What Is a Size Zero? If You're a Designer, It's Whatever You Want.Hillary Crosley Coker9/30/14 2:00pm3243EditInvite manuallyPromoteDismissUndismissHideGo to permalinkWhat size do you wear? If you’re a Hollywood star like Christina Hendricks, Juliana Margulies or Amy Adams, your stylist probably just grabs a size zero. Welcome to vanity sizing.