Rihanna Sings 'What's My Name' at Marquee's Boom Box

Check out Rihanna singing along to her smash hit “What’s My Name” during The Cosmopolitan’s New Year’s Eve celebration in Las Vegas!

With a champagne flute in one hand and a mic in the other, the 22-year-old pop star took over the DJ booth at the VIP Boom Box inside Marquee Nightclub along with Jay-Z and Kanye West.

Also in the room: Beyonce and younger sis Solange Knowles, Olivia Munn, Diddy, and Kings of Leon bassist Jared Followill!

Earlier in the night, Rihanna hosted Pure Nightclub’s NYE bash.