At just nine years old, pre-teen trendsetter Willow Smith has started a hair-whipping movement with her song "Whip my Hair." The pint-sized singer's first single has been out just a few weeks and she's already amassed a bevy of tiny dancers, whipping their hair real good. Our friends over at Popeater also noted Willow's "army of hair-whipping gal pals" doing their thing on YouTube... The above clip was assembled in less than three hours, according to choreographers Monica Warr and Kae J. These little girls better work!