Dakota Fanning. Photo by Getty Images.

Where: The Sundance Film Festival premiere of Very Good Girls.

When: January 22

What: A Miu Miu top, a Louis Vuitton sequin-embroidered tweed mini skirt and Azzedine Alaia heels.

Why: The slit of bare midriff adds tasteful sexiness without inducing hypothermia. A deep red lip and loose strands strike the balance between grown-up and carefree.

Photo: Getty Images