AP / Bauer-Griffin 1 / 24
AP / Bauer-Griffin 1 / 24

It's easy to see why Simon Cowell was eager to add Britney Spears to his panel of "The X Factor" judges.

The "Toxic" singer, 30, officially announced her participation in the show during the FOX Upfront event in New York on Monday. Spears slipped into a body-hugging, white minidress and Giuseppe Zanotti shoes to join Cowell, 52, L.A. Reid, 55, and new judge Demi Lovato, 19, on stage.

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"I am so excited about this whole experience. It's going to be so much fun and so different from anything I've ever done," Spears told the crowd. "I'm ready to find the true star."

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Spears -- engaged to Jason Trawick, 40, since December -- changed into another sexy number backstage, opting for a purple Alexander Wang minidress. "I couldn't be more excited to join The 'X Factor' judging panel. I'm a huge fan of the show and now I get to be a part of the action," she told Us Weekly in a statement Monday. "Simon and L.A. better watch out!"

Also on display: Spears' 3-carat Neil Lane engagement ring, worth an estimated $90,000!

Lovato, who recently dyed her hair blond, turned heads in a colorful design by Falguni & Shane Peacock. "I am totally stoked to be here," she exclaimed. "I'm excited to represent my generation."

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Spears and Lovato have replaced former judges Paula Abdul, 49, and Nicole Scherzinger, 33, who were fired from "The X Factor" in January. Ex-host Steve Jones' replacement has yet to be announced.

This article originally appeared on Usmagazine.com: "Britney Spears Wears Two Sexy Mini-Dresses for 'X Factor" Presentation"