Hottest Celebrity Hookups of 2012
Rihanna, Rob Kardashian
The "S&M" singer and E! reality star shared an action-packed day together in August. The twosome went go-karting at Racer's Edge Indoor Karting in Burbank, Calif., and then headed to L.A.'s Playhouse nightclub later that evening. "They were sitting closely at the club, whispering in each other's ears and clearly flirting," an eyewitness told Us.