From dog-walking to nights on the town, it’s clear wide headbands are the accessory of choice for on-the-go celebs. Those of the stretchy variety provide a chic alternative to the quintessential baseball cap on bad hair days, while a patterned chiffon scarf adds a delicate, laid-back touch to a cocktail-ready ensemble. Sienna Miller chooses a long gray length and tucks the extra into her belt (a new substitute for Rapunzel extensions?). Out in Los Angeles, tabloidites Nicole Richie and Lindsay Lohan add that beach bum je ne sais quoi to their takes on the trend. But tennis star Maria Sharapova wins the purist award for her look: a swoosh-emblazoned Nike sweatband paired with a rocker-esque striped vest. U.S. Open opponents beware: This girl’s got game and fashion savvy.