16 It-Girl Approved Halloween Costume Ideas

How does one find the perfect Halloween costume that is equal parts unique, alluring, and impressive? Turn to our seasoned panel of experts in everything cool, the It-girls of the fashion world, of course.

Scroll down for an assortment of ideas from Alexa Chung, Mary-Kate Olsen, and more, including everything from fashionable spins on classic costumes to inspired takes on movie characters.