Maybe blondes really don’t have more fun. Recently, traditionally towheaded babes like Charlize Theron, Jessica Simpson and Cameron Diaz have all jumped on the brunette bandwagon, a move that entails much more than a simple dye job. Most important, says colorist Rita Hazan, is to be certain about your decision, since it can be damaging to go back to blonde after trying brunette. “If you’re not completely sure, choose a darker blonde instead. You don’t need to go really dark brown to get a dramatic effect,” she says. Mark Townsend, celebrity stylist for Vavoom hair care, says highlights are best, since all-one-color brunettes can look matte. “Definitely don’t go more than two levels darker at once,” he warns. It’s also important to take the overall health of your hair into consideration before taking the plunge.“Very processed, bleached hair is tricky—the roots will absorb the nice rich shade but the ends won’t,” says colorist Sharon Dorram Krause. Finally, remember to adjust your style. Waves and long layers are flattering for richer tones, while long and straight (amazing for buttery blondes à la Gwyneth) is too Goth with deeper shades. A perfect example: The difference between a slightly scary Angelina on the eve of her Oscar win compared to today’s breathtaking beauty.