Lady Gaga
The Mother Monster helps give birth to a big fat New Year while performing during The New Year's Rockin' Eve show in Times Square.
Read all about what Gaga and other stars did and where they partied New Year's Eve
Pitbull & Justin Bieber
The hitmakers hang together for a rockin' NYE in NYC.
Karina Smirnoff
No ball drop here! The hot Dancing With the Stars hoofer just rolls with it as she hosts Joonbug's End of the Year Bash at Bowlmor Lanes in Times Square, NYC.
Bill & Giuliana Rancic
The E! star and her hubby sieze the moment as they kiss-in 2012 at the NIVEA party in Times Square.
Emmy Rossum
The Shameless star shines on Carson Daly's NYE show in Times Square.
Will.i.am
The Black Eyed Peas frontman shifts into Vegas deejay mode to welcome 2012 at Surrender Nightclub in the Wynn.
Kourtney Kardashian & Scott Disick
The E! reality stars clean up real nice as they formally welcome the New Year at Paris Las Vegas.
Joel & Benji Madden
The Good Charlotte bros rock in the New Year at Chateau Nightclub in Paris Las Vegas.
Kyle Richards & Mauricio Umansky
The Bev Hills Housewife and hubby welcome the New Year and check out music legend Stevie Wonder's show at the Chelsea at the Cosmopolitan in Vegas.