Gomez makes a festive appearance at the Jingle Ball concert in Sacramento, Calif. Plus: Kristin Cavallari, Blake Lively, Prince Harry and more

DIAMONDS ARE FOREVER

Let the bidding wars begin! A black-clad Sarah Jessica Parker takes a sneak peak at the soon-to-be auctioned personal treasures of Elizabeth Taylor during the PEOPLE magazine and Christie's Elizabeth Taylor Collection preview event Thursday in New York City.