By Lynette Rice
Updated May 14, 2012 at 08:08 PM EDT

The worst kept secret at Fox was made official at the network’s upfront presentation in New York today: Britney Spears and Demi Lovato will join The X Factor as judges in the fall.

Spears and Lovato joined fellow judges Simon Cowell and L.A. Reid on the Beacon Theatre stage very briefly but long enough to express their enthusiasm for their new high-profile gigs.

“I’m ready to find the true star,” gushed Spears, who wore a very tight and very short white dress for the occasion.

“It’s an honor to be standing next to you,” continued Lovato (and she meant that for Cowell, not Spears). She, too, was clad in a short and tight tog. “It’s an honor to represent my generation.”

Spears and Lovato replace Paula Abdul and Nicole Scherzinger, who only served as judges for one season. The X Factor will return in the fall, when Cowell promises the show will be “number one music franchise.”

“This is the Rolls Royce” of music shows, Reid told advertisers Monday.

Strangely, the presentation ended with a performance by Mary J. Blige — not Spears or Lovato or even the Glee actors like Lea Michele or Darren Criss, who were also in attendance.

Spears tweeted a photo of herself alongside her new coworkers Reid, Cowell, and Lovato at the Beacon, but didn’t add further comment on the social networking site.