Paris Hilton got on the microphone at a packed Las Vegas nightclub and lavished Christina Aguilera with praise - and in the process revealed a celebrity secret.

"Congratulations to the most beautiful pregnant woman in the world. You're gorgeous," Hilton announced at about 2 a.m. Sunday at an Aguilera-hosted party at LAX Nightclub in the Luxor.

Aguilera, who has never confirmed being pregnant despite a visible bump beneath her pink chiffon mini-dress, appeared temporarily shocked as she sat in her perch in the elevated VIP booth. She sank her head into the shoulder of husband Jordan Bratman as her friends looked stunned. TMZ has video of the blunder.

[People]