Happy New Year!
So, how exactly did they bring in the New Year? We've got all the details!
On the east coast, a Versace-clad Lady Gaga was on hand at Dick Clark's New Year's Rockin' Eve in NYC's Times Square, performing in a Swarovski crystal-encrusted black cat suit with black platform shoes.
And never one to shy away from a quick wardrobe change, the pop superstar switched up her look, donning a silver Atelier Versace beaded gown with a silver crystal-covered headpiece to watch the ball drop at midnight.
On the west coast, Kanye West and Fergie kicked off the New Year at the opening of 1 OAK in Las Vegas, where Kanye (who dubbed himself YEEZYWORLDPEACE for the evening) deejayed the party, spinning hits for partygoers for three hours!
Fergie, who hosted the affair, was spotted kissing hubby Josh Duhamel at midnight. And while she didn't perform, the Black Eyed Peas singer sang along to '80s music at her table, and was entertained by a magician who performed tricks for partygoers as well.
Joining Fergie and Kanye at the lavish affair were Joseph Gordon-Levitt, Kid Cudi, Topher Grace, Big Sean, Jason Ritter and David Katzenberg, among other celebs.
Meanwhile, John Legend performed at Moon Nightclub at Palms Casino resort in Sin City, and partied the night away with his fiancé, model Chrissy Tiegen, whom he smooched at midnight.
Over at Tao in the Venetian Hotel, Kim Kardashian hosted a party in a white Gucci long sleeve mini dress, kicking off the night saying, "It's a tradition to ring in the New Year here at Tao!"
The E! reality starlet was spotted singing and dancing along to a Britney Spears song, and then her mom, Kris Jenner, who was also on hand, requested that the DJ play Kim's song, "Jam."
As the clock struck 12, Kim told partygoers, "I am so excited and can't wait for 2012 to come. Countdown with me!"
Meanwhile, Samantha Ronson spun at a party at Lavo in the Palazzo.
Outside of the States, Prince William and Kate Middleton spent New Year's Eve at a private party held in a tent in the back garden of the Duchess of Cambridge's family home in Berkshire, England, according to People.
Kate's sister, Pippa, hosted the affair, which was described as a "canvas palace" to the mag, and included more than 100 partygoers.
Prince Harry, who was absent from the party, brought in 2012 in Switzerland, at ski resort Verbier.