Hot Trend: Retro Fashion

See Christina Aguilera, Johnny Depp, Beyonce and eight other stars who take inspiration from the styles of decades past. By Serena Kappes

MARY-KATE OLSEN & SCARLETT JOHANSSON: '90s

Both Mary-Kate Olsen (left) and Scarlett Johansson (right) have a "very '90s grunge feeling of layering, looking like you're thrown together," says Kaufman. "It's sort of like, 'That sweater's lying on the chair – I'll throw that on top of this.' The look is supposed to be, 'I didn't plan this. These are clothes I just had sitting around.' "