Kate Upton is bringing the Britney Spears nostalgia [1] to Lip Sync Battle. The Sports Illustrated stunner went up against Ricky Martin and re-created the iconic video [2] for "Baby One More Time," complete with dance moves, pigtails, and sexy schoolgirl outfit. Even her fellow Swimsuit Issue cover girl Chrissy Teigen couldn't believe her eyes. Get a load of Kate's performance above now.