Last week, the stars aligned at New York's South Street Seaport to celebrate the launch of Matthew Williamson's second collection for H&M, the first of which debuted in stores only a week before. Performances by Grace Jones and music by DJ Michel Gaubert and DJ Hanna Hanra provided entertainment while hosts and hostesses dresses as sailors added a beachy, tropical vibe to the soiree. Mary-Kate Olsen, Helena Christensen, and Lucy Liu came out to admire the collection, which is set to arrive in stores on May 14. Williamson himself had this to say: "Working with H&M has been such a wonderful experience. The global launch event in New York City was a spectacular soiree. I was delighted to see so many of my friends from the fashion world support this collection." The collection will feature colorful prints and sophisticated tailoring, in addition to a men's line which will be Williamson's first. Click the slideshow to see party pics!