Jay-Z was the main attraction in Las Vegas, where he celebrated the Cosmopolitan and Marquee Nightclub's opening with Coldplay and special guests John Mayer and Kanye West. Chris Martin and Jay-Z's famous wives Gwyneth Paltrow and Beyonce Knowles weren't spotted on the gray carpet before the show, but a ton of famous fans were out. Channing Tatum and Jenna Dewan indulged in some PDA for the cameras, while Jessica Szohr, Kirsten Dunst, Kristen Davis, a slick-haired Kellan Lutz, and Mark Wahlberg all smiled solo. John, meanwhile, kept his distance publicly from some ladies he's been linked to lately like TV chef Giada De Laurentiis, who denied a link to him, and Rashida Jones. Beyonce was also on the list of performers, as she joined Jay-Z to perform "Young Forever," just like at Coachella.