09/28/2011 AT 10:00 AM ET
File under: friendly exes. Joe Jonas and Ashley Greene seemed at ease hanging out and taking in the party scene at Las Vegas’s Tao Nightclub, which was celebrating its 1000th night in business with a star-studded bash hosted by Jay-Z. Jonas dined with friends at the downstairs restaurant before heading up to the club, where he joined a table with Cheryl Burke, her DWTS partner Rob Kardashian and Greene, who was hanging out as part of the group. Meanwhile, up in a skybox: Kelly Clarkson and her band had a prime view of the dancefloor below – as well as bottle service.