Olivier Rousteing has a lot to celebrate lately. The head designer of Balmain recently collaborated with Beats By Dre and opened a new boutique in Los Angeles. Can you say “winning”? To celebrate his recent accomplishments he threw a party a couple of nights ago and invited all of his fab friends. In attendance were Kerry Washington, Halsey, Kim Kardashian West, Aimee Song, Monica and more. Check out a few images of the celebs in attendance decked out in Balmain, of course.