Britney Spears, Demi Lovato, & Khloe Kardashian at The X Factor USA Party

Last night, X-Factor castmates including L.A. Reid, Britney Spears, Khloe Kardashian, Demi Lovato and Mario Lopez took the red carpet to party it up at FOX's The X-Factor Finalists Party at the SLS Hotel in Beverly Hills to celebrate the finalists of this season.

Britney glammed up in a black All Saints dress with zipper details that she paired with a pair of Herve Leger shoes. Khloe also got the LBD memo in a turtleneck Skaist-Taylor dress that she paired with metallic Gianvitto Rossi shoes, a Valentino bag and a power red lip.