The party's always grand when the worlds of music and fashion collide. Jay-Z, the certified King of New York, co-hosted a Fashion Week party with GQ for his Rocawear clothing line. The soiree boasted one of the most coveted guest lists in town, including a private performance by Trey Songz and an appearance by Kanye West, Serena Williams, Common and Melanie Fiona. We hear Solange manned the DJ booth all night. Check out how these celebs celebrated fashion.