Singer plays dress-up, portraying Janet Jackson, TLC, Diana Ross and more in new Joseph Kahn clip. By Rebecca Thomas, with reporting by Kelly Marino Keri Hilson on the set of her music video for “Pretty Girl Rock” Photo: MTV News It takes more than a dollop of self-confidence to hang the chorus of your song on the bordering-on-obnoxious slogan for an ’80s shampoo commercial . But when Keri Hilson sings, “Don’t hate me ’cause I’m beautiful,” on her latest track, “Pretty Girl Rock,” she wants the ladies to sing along. Co-written by Ne-Yo (who gave fed-up women everywhere Beyonc
