The cozy couple continue their joint birthday celebration in Sin City. Plus: Sienna Miller, K-Fed and more

GETTING 'SOCIAL'

Nick Lachey and girlfriend Vanessa Minnillo, who share a Nov. 9 birthday, cozy up Saturday at Social House in Las Vegas's Treasure Island Hotel – just one stop in a full Vegas weekend during which Lachey also performed in concert. At his Saturday show at the Luxor, Lachey said of his new relationship, "I found love again," before cracking a joke, "in fact, I got married this weekend here in Vegas."