LAS VEGAS -- Britney Spears stands onstage, face low and obscured by her cowboy hat. Her lips aren't moving, except to laugh, but she's not here to practice singing -- she's at the Pearl to move.

All afternoon, everyone's been waiting for Britney to rehearse for [article id="1568994"]her VMA performance[/article]. Britney Watch, as you might call it, takes the form of excruciatingly long periods of waiting punctuated by brief bursts of news, which can almost resemble activity from afar, even when nothing's actually happened yet. Britney's in the air, Britney's landed, Britney's in the building. There's the anticipation (what will she be like?), the worry (what if she doesn't show?), and the doubt (can she still pull it off?). But if the skeptics saw what a few of us at MTV News were privileged to witness late Friday afternoon (September 7) at the Pearl Concert Theater in the Palms Resort Casino, they would doubt no more.

Britney as a tabloid figure has loomed so large of late, it's hard to imagine that there was a time when it was just Britney the performer. Britney the dancer. Britney the star. And while she wasn't yet at full steam -- after all, these were dry runs at the Palms to get her blocking straight and stage lighting situated -- glimpses of what she used to be and what she could still become were there even in these early rehearsals. "Gimme More" might not have won everyone over on first listen (see [article id="1569158"]"Britney Spears' New Single Gets Club-Tested In Vegas"[/article]), but it's kind of like "Slave 4 U" or "SexyBack" -- the videos in those cases helped sell the songs. But in this case, Britney's performance this Sunday will not just help sell the song, it will help sell her.

"OK, here we go. Three, two, one, track," a female voice announces over the PA system in the Pearl. Spotlights sweep back and forth, strobes flash, and a silver-gray curtain parts. Spears stands to the side, in jeans and a white tank top that reads "James," hat tipped over her face. The song starts, but she turns her back during the opening line, "It's Britney, bitch," striking a pose of pure attitude.

She's flanked by a few dancers, who at first seem asleep, crouched low, but come awake once Britney drops the "bitch" line. More come out as Britney sings, "Gimme more," until she's got more than a dozen onstage. A half-dozen aerialists are also to join the action, later on, though they weren't present at this stage in the rehearsal.

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.

It could just be a sexy dance move, or it could be symbolic for Brit: To get back to the top of her game, she has to give a little too. And then, she turns her back to everyone once more for her closing line -- "I just want more" -- leaving everyone watching wanting more too.

(Britney Spears isn't the only one warming up for Sunday -- check out Kanye West testing out his intimate VMA suite, Foo Fighters jamming with Cee-Lo and more, and Nicole Scherzinger and Lil Wayne trying out their sexy preshow performance.)

Wait -- don't cash out on the VMAs just yet! From Britney's sultry comeback performance to the big winners, you saw it all -- well, almost everything! Get yourself even richer with our wall-to-wall show coverage, party reports, videos and loads more at www.VMA.MTV.com. For reports, photos, video and much, much more from previous VMAs, dive into the VMA archives.