Less than a day after Britney Spears debuted her new music video for 'Till the World Ends', she is already fighting off speculation that she used a body double in the video.

Celeb gossip website Oh No They Didn't! suggest that choreographer and backup dancer Tiana Brown replaces Brit's bod in scenes of the video for the Ke$ha-penned dance hit -- accusations that the Spears camp denies. Brown danced on the road beside Britney on the 'Circus Starring Britney Spears Tour' and has worked with other dancing divas, including Christina Aguilera, the Pussycat Dolls, Jennifer Lopez and Fergie. But, according to Ms. Spears' official website, when it comes to the video -- it's Britney, b--ch!

The superstar's new album 'Femme Fatale' debuted on the Billboard 200 chart at No. 1 and sold 276,000 copies in its first week -- making it Brit's sixth No. 1 album. Whether or not she solicited the help of a stand-in for the video, there's no denying that this femme fatale is back on top where she belongs.