Credit: Noel Vasquez/Getty; Jon Furniss/WireImage; Jim Spellman/WireImage

Leaders of the band!

Olivia Wilde, Nicole Richie and Hilary Duff are topping off their 'dos with ornaments. Whether sparkly or sleek, "headbands add polish to styles without looking stuffy," says stylist Marcus Francis, who adorned Duff's hair Jennifer Behr's Leather Dinosaur Studded Headband ($162, for an October 10 NYC event.

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The trick to looking stylish in one is picking the right band for your tresses. "On thin hair (like Wilde's), a narrow band adds fullness," says Francis. "A wider band helps course hair (like Richie's) maintain shape."

Above all, warns Francis, "keep hair soft and simple. Hair spray makes the look stiff and too retro!"

Wilde, who is constantly one of Us' celebrity hair crushes, tells Us Weekly, "I also like to wear headbands with a messy bun."