Britney Spears** continued her spectacular sartorial run on The X Factor Nov. 21.

The new judge, 30, rocked a midriff-baring Fannie Schiavoni top, a curve-hugging Paco Rabanne skirt and Gio Diev heels. Moments before the show, the pop star tweeted that she was "blasting" her new song with will.i.am, "Sream & Shout," backstage in her dressing room. "Can you hear this, Khloe Kardashian?"

All four of Spears' teen acts performed during the telecast, but it was 13-year-old Carly Rose Sonenclar who stole the show with her rendition of Judy Garland's "Somewhere Over the Rainbow" from the 1939 classic The Wizard of Oz.

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"You are absolute force of nature. I don't know where it comes from, and when you least expect it, you dig deeper and you pull out the big one. But that time you pulled out a big two -- you went to two big notes. You only needed one, and you went to two!" L.A. Reid** told Sonenclar, who dedicated the performance to her older brother. "I don't know how you do it."

Simon Cowell** added, "I've heard that song a lot of times, and that was one of the best versions of it I've ever heard. Seriously, amazing. And you know what? When I said to Vino [Alan], 'I think you're going to be No. 1 next week,' I think I've changed my mind."

The show's other new judge, Demi Lovato, was equally blown away. "It's like you're an alien or something -- but that's okay, because I love aliens!"

A proud Spears agreed with all three judges. "I will never get over the fact that you're 13. It's unreal," she told Sonenclar. "You are unreal. It's amazing!"

Two more acts will be eliminated during The X Factor's live results show Thursday, Nov. 22, at 8 p.m EST on FOX.

This article originally appeared on Usmagazine.com: Britney Spears Rocks Sexy Crop Top on The X Factor