MTV exclusive behind the scenes of Britnet Spears lip sync rehearsal.

I can't blame MTV for pushing the heck out of Britney Spears' "Comeback" performance this Sunday. But let's get real for a moment. Britney isn't going to sing live. She'll be putting on a karaoke show with a bunch of back up dancrs. Any real performer would have the guts to sing live.
MTV:
With each run-through, a choreographer gives Britney more steps to weave in as she gets more comfortable with the routine — and as she gets more comfortable, that white tank top edges up to expose even more midriff. Her dancers get more suggestive, pulling and pushing and dragging each other across the stage. But Britney remains dominant, treating one like a boy toy, stepping over him, and tossing him aside when she's done with him. That part's easy — a move that takes a little longer to learn is to fall into a column of her dancers, who push her back standing up, like one of those trust exercises you do at camp.