It was a memorable New Year's Eve for the Cosmopolitan Hotel party goers. The posh hotel opened its doors at the strike of midnight with a performance from Jay-Z, ColdPlay's Chris Martin, and "surprise" guests Beyonce, John Mayer and Kanye West. And their celeb friends like Taraji Henson, the Whitakers, Christina Milian, Brandy and more came out to party too.
We've got the clock striking party pics when you read on...