Dance fever swept spring runways this year, from the sleek chignons at Zac Posen to Marc Jacobs' gauzy pastel leggings. And now cosmetic companies are toeing the line, with ballet-pink palettes and ultrafeminine scents, like the peony-inspired Wish Pink. But the biggest beauty trend this season? Simple updos, a basic in any dancer's repertoire. "Ballerina buns are a reaction to what we see on the red carpet," says Redken hairstylist Guido Palau, who created knots Ã la Martha Graham at Bottega Veneta and Marc Jacobs. "Every actress has long, wavy hair now. It's so predictable, it's boring." Updos can also be sexy, adds Palau. "When you wear your hair up, you elongate the neck. The more feminine and fussy the details on your clothes are, the more clean and austere the hair should be." Especially if you're not actually onstage.