The 27-year-old actress stepped out for the event alongside 22-year-old actor Ansel Elgort.
Lily wore a Valentino gown and Tiffany jewelry. As a Lancome ambassador, she went with an avant-garde beauty look that was designed to give her an ethereal robotic edge.
FYI: Ansel is wearing a navy Prada mohair jacquard smoking jacket with a black satin shawl lapel and black tuxedo pants, a white pipeline smoking shirt, black satin bow tie and lizard dress shoes. He paired the suit with a Chanel watch and cuff links.