Spears joined executive producer Simon Cowell and fellow judges Demi Lovato and L.A. Reid on stage. The multi-million-dollar judge dressed in a white, body-hugging, mini with Giuseppe Zanotti gold shoes.
The surprisingly demure singer told the crowd, "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… I'm ready to find the true star."
Spears, engaged to agent/co-conservator Jason Trawick, then changed into another sexy getup backstage, opting for a purple Alexander Wang mini, complemented by her 3-carat Neil Lane engagement ring, worth about $90,000.
Former Disney star Lovato, 19, who recently dyed her hair blonde, also 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." Lovato is reportedly getting $1M for her salary.
Revamped pop megastar Britney Spears officially announced her $15-million decision to join "The X Factor" Monday at the FOX upfronts in NYC, and used the photo op to display her rockin' new body.