Fashionistas in many forms turned up to Thursday night's YSL "Belle d'Opium" fragrance launch in NYC. In fact, we're not quite sure what the dress code was. Maggie Gyllenhaal donned a strapless magenta dress, model Irina Shayk opted for a shrunken (and tight!) leopard jumpsuit and Ashley Olsen wore a trenchcoat and a headscarf. Take a look at the pics below and let us know who was the belle of this ball, and whose ensemble was a bust.