Jennifer Lawrence may play one tough heroine on the big screen, but our December cover girl shows a candid and glamorous side in the holiday issue— out on newsstands on November 15th. Lawrence talks about everything from her workout regime, which she admits that "nothing can motivate me," to growing up with two older brothers, and that infamous trip up the stairs during last year's Oscars. "I fell because the fabric of my dress got stuck under my foot. I can't walk up stairs, ever. In fact, I tripped walking up some stairs just yesterday, and my publicist was cracking up." In our exclusive behind-the-scenes video, Lawrence kept her balance (while in Fendi pumps) as she took fashion to new heights at the 17,000-square-foot hangar at the Jet Center L.A. dressed in everything from Balenciaga, Alexander McQueen, Céline, and Valentino, all shot pre-pixie hair cut! Click the play button to get a sneak peek at some of Lawrence's white-hot couture looks, then make sure you pick up InStyle‘s December issue, on newsstands and available for digital download beginning Friday, November 15.