Sofia Vergara and Joe Manganiello spent their New Year's Eve in Las Vegas, where they caught a performance of Britney Spears [1]'s Piece of Me show at Planet Hollywood. They were joined by Arnold Schwarzenegger [2] and his girlfriend, Heather Milligan, in the audience. Sofia and Joe, who got engaged on Christmas Day [3], recently returned from a Hawaiian getaway to celebrate Joe's 38th birthday. It was an exciting 2014 for the couple, and it looks like 2015 might have even more in store!