Michael Cera attending the Dimension Films' special of Youth in Revolt, sponsored by Three-O Vodka, in NYC.
Jennifer Lopez and Marc Anthony eating caviar at NYC's Charles Restaurant on New Year's Eve.
Kevin Federline and girlfriend Victoria Prince sharing guacamole and margaritas and at Cabo Wabo Cantina in Las Vegas.
John Mayer hanging with his dad Richard on New Year's Eve after his performance at The Joint in Las Vegas.
See the day's top celeb photos.
Christina Milian getting a G2 Lifestyles Maternity Mat at her baby shower in the Hollywood Hills.
Sofia Vergara partying with Diesel's founder Renzo Rosso at the Pelican Hotel in Miami Beach.
DJ Theo and DJ Short Kutz spinning at Quo in NYC.
Kellan Lutz doing a New Year's Eve countdown at Klutch in Miami Beach.
Katharine McPhee wearing an Illia tank in NYC.
Jessica Szohr shopping for boyfriend Ed Westwick at the Diesel store on 5th Avenue in NYC.
Jessica Biel, Emile Hirsch, Lupe Fiasco and musician Kenna boarding a flight at LAX to Africa to climb Mt. Kilimanjaro in Tanzania for Summit on the Summit.
AnnaLynne McCord ringing in the New Year at Wall at the W Hotel South Beach.
Mariah Carey and Nick Cannon having a private New Year's Eve afterparty at Cafeteria in NYC.
DJ Berrie spinning for a crowd including Hayden Panettiere and Kevin Connolly at the Fontainebleau in Miami.
O'Neal McKnight performing for a packed crowd at Amnesia in NYC.
The Real Housewives of New Jersey's Danielle Staub hosting a party at China Club in NYC.
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Leighton Meester crawling on the stage at a Grey Goose sponsored bash at The Underground in Chicago.
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