New Year's Eve 2012: Parties and Celebrities

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HAVING A BALL

Looks like Lady Gaga found someone – or something – to kiss! Following her New Year's Rockin' Eve performance in N.Y.C.'s Times Square, the singer plants a smooch on a sphere before launching the official ball drop with Mayor Michael Bloomberg (not pictured).

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SHOW-TOPPER

Who can resist a hunk in a hat? Certainly not Fergie, who preps her pucker for hubby Josh Duhamel at the grand opening of The Mirage's 1 OAK Las Vegas, where she served as host and also performed at the New Year's Eve event.

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HEY MR. DJ!

Also at the 1 OAK Las Vegas blowout: Kanye West, who got the party started by spinning tunes under the pseudonym YeezyWorldPeace.

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SHEER DELIGHT

Days after making a casual McDonald's run in London, Rihanna glams it up for the Sean "Diddy" Combs-hosted CIROC: The New Year 2012 bash in Miami.

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TIMES PAIR

Pitbull and Justin Bieber buddy up in N.Y.C.'s Times Square, where each appeared on New Year's Rockin' Eve. Pitbull performed his hits "I Know You Want Me" and "Give Me Everything," while the Bieb rang in the new year with something old: the Beatles classic "Let It Be."

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RAISE YOUR GLASS

Joined by Dancing with the Stars pro Mark Ballas and her mom Kris Jenner at Las Vegas's TAO Nightclub at the Venetian, soon-to-be divorcée Kim Kardashian leaves behind a tumultuous 2011 and toasts to being in 2012.

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COZY COUPLE

Vowing to and enjoy life following her recent double mastectomy, Giuliana Rancic cuddles up with husband Bill at the NIVEA Kiss Stage in New York's Times Square.

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FORGET 2011!

Also at the NIVEA Kiss Stage in N.Y.C., Cee Lo Green wows the crowd with his take on John Lennon's "Imagine" for NBC's New Year's Eve with Carson Daly special.

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OUT OF THIS WORLD

In Los Angeles, a very Jetsons-esque Nicki Minaj looks ready for the future – which will likely include an appearance at the Feb. 12 Grammys – while performing "Super Bass" on Dick Clark's New Year's Rockin' Eve.

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BOWLED OVER

Check out that footwork! Dancing with the Stars pro Karina Smirnoff has a heel of a time bowling with a bottle at Joonbug's End of the Year Bash in N.Y.C.

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SPARKLE & SHINE

Designer Lauren Conrad and former fellow The Hills star Stephanie Pratt make a stylish statement at the Hyde Bellagio celebration in Las Vegas, where Leona Lewis, Wilmer Valderrama and Eliza Dushku were among the revelers.

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QUITE A CONTRAST!

Also partying at the Hyde Bellagio, a white-hot Sofia Vergara strikes a pose with a darkly dressed Joe Jonas – but was he as entertaining as Kermit the Frog?

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ICING ON THE CAKE

Singer Bruno Mars caps off a blockbuster year – which included winning a Grammy, a Billboard Music Award and an American Music Award – with a sweet celebration at Las Vegas's The Bank Nightclub at the Bellagio.

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COLD SHOULDER

Shameless star Emmy Rossum turns up the heat in a strapless red dress during an appearance on NBC's New Year's Eve with Carson Daly in N.Y.C.

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HOST WITH THE MOST

A dashing Sean greets his guests, which include actress Vivica A. Fox (pictured), Gayle King and Star Jones, at the CIROC: The New Year 2012 bash in Miami, held at a private estate.

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GETTING CHEEKY

Someone's feeling frisky! Brandy gives a peck to reported new beau Ryan Press at The Cosmopolitan of Las Vegas Celebrates New Year's Eve party, where music legend Stevie Wonder was the star attraction.

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HATS OFF!

After showing off her ice-skating skills, Holly Madison flaunts her famed figure while welcoming 2012 at the Chateau Nightclub amp Gardens in Las Vegas.

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