After spending Christmas in a teeny bikini on Kauai, Katy returned to Los Angeles to ring in 2012 with several pals at hot spot Soho House, says the New York Post. "Katy was in a private room with a group and she seemed to be in a great mood," relays an insider. "She spent most of the night dancing and laughing with friends." Among those she was seen chatting up and smiling with was a long-haired guy. Says the onlooker, "One wouldn't have ever even known that her husband had just filed for divorce."