Summer's Hottest Hats

Not just for bad hair days, the toppers Jessica Alba, Ashlee Simpson and more wear keep them looking and feeling cool

GWEN STEFANI

Why we love it: It works in any season. And tilted over one eye, the black topper makes the singer look like a mysterious femme fatale.
Where we'd wear it: For cocktails at a speakeasy-style bar or a swanky lounge, complete with a bright red lip and sexy heels