Floyd Mayweather Jr With DJ Fred Matters

Alistair Overeem With Guest

Kaskade brought in the New Year at Marquee Nightclub at The Cosmopolitan of Las Vegas. The DJ, named America's Best DJ by DJ Times, took to the booth just before midnight and led the packed club in the countdown, which was displayed on Marquee's 40 foot LED screen above. He shouted out to the crowd, "Who is going to go twelve hours with me? Come on!" He then proceeded to take club goers on a journey that lasted from midnight to noon on January 1, believed to be a US record for the longest DJ set.

Spotted in the crowd: Kyle Richards and her husband Mauricio from The Real Housewives of Beverly Hills as well as soap opera stars Nadia Bjorlin and boyfriend Brandon Beemer from the E! show Dirty Soap. Electronic dance music vocalist Nadia Ali also began 2012 at Marquee. UFC fighter Alistair Overeem celebrated his weekend victory over Brock Lesnar in a cabana.

Floyd Mayweather and 50 Cent made a late night arrival at Marquee, taking over several tables in the hot spot's Boom Box room with a large group of friends as DJ Fred Matters entertained them with a selection of hip hop. Lil Kim joined the group, requesting her own songs.

Having heard about Kaskade's plan to spin from 12 to 12 for 2012 the celebs kept coming.

Wilmer Valderrama arrived around 3:30 am to take in the sounds of the Kaskade marathon from a table on the dance floor, as did Lauren Conrad and Frankie Delgado. Topher Grace also was a late night arrival to Marquee at around 4 am and Mark Ballas arrived just before 5 am to catch his set.

True to his word, Kaskade played a 12 hour set, treating fans staying until the end to a brand new mix.

Photos Courtesy Of: Al Powers/Powers Imagery