Beyonce Knowles has an alter ego and her name is Sasha Fierce.
''She's the party girl, she's Bootylicious,'' says the singer in the promotional material for her new double album, I Am ... Sasha Fierce, in stores Tuesday. ``She is, but I'm not . . . I'm finally revealing who I am.''
The contradiction built into that brief comment says much about Beyonce's artistic predicament.
A child talent-show winner molded into a pop star by her notoriously driven father, she is a creature of the stage, like Britney and Christina, the pop stars with whom she might have continued to be lumped if her husband Jay-Z -- and, more important, her own ''rapperly'' vocal gifts -- hadn't helped her secure a spot in hip-hop's firmament. Yet because the world of hip-hop soul expects its divas to be ''real,'' she's often criticized for seeming distant in her own performances and refusing to expose herself.
