Jackie Warner and Colin Cowie.

Cosmopolitan of Las Vegas Hosts Star-Studded Grand Opening

The place to be to ring in 2011? For many of Hollywood's elite, it was The Cosmopolitan of Las Vegas, the city's newest and most glamorous resort, which kicked off a grand opening celebration with concert performances from JAY-Z and Coldplay, plus guest surprises by Kanye West, Beyonce and John Mayer.

Coldplay kicked off the evening with a 12 song set, which included Yellow, In My Place and Clocks. To ring in the New Year, JAY-Z joined Coldplay on stage for a rendition of Lost, followed by a countdown to midnight. JAY-Z took the stage for the first hours of 2011 and was joined by Kanye West for an impromptu freestyle performance of Run This Town, Can't Tell Me Nothing and Runaway. As Kanye left the stage, John Mayer joined pal JAY-Z with his guitar for several songs, including Public Service Announcement and 99 Problems. The ultimate collaboration of the evening came when Beyonce joined her husband on stage for Young Forever. She continued to wow the crowd, bringing Coldplay frontman Chris Martin back out for an acoustic duet of her hit, Halo.

Gallery: Cosmopolitan Las Vegas Grand Opening