Proving no one does it like Lanvin, a slew of fashion A-listers came out to the French fashion house’s Halloween extravaganza on Friday to celebrate the recent opening of the Madison Avenue flagship. The spooky soiree was the most talked about fashion party of the weekend — even out-spooking Heidi Klum’s annual fete — and was packed with costume bearing fashionistas. Anne Hathaway donned a leopard print jumpsuit by the label, while Canada’s Brad Goreski channeled pint-sized fashion blogger Tavi and Janet Jackson sported a ‘stache. Elbaz transformed the boutique into a festive fun-house complete with 2,000 balloons covering the front of the store. Guests were treated to expertly concocted cocktails while drag queens vamped up as Dolly Parton and Tina Turner took to the stage that was designed like a giant Lanvin dress box.