Words are, Britney hired a choreographer, dancer and co-captain of her tour as a stunt double in the Ray Kay-directed music video.
Hours after "Till the World Ends" music video was premiered, Britney Spears was hit with allegation that she didn't do the dance in the Ray Kay-directed video by herself. Rumor has it, she used a dancer named Tiana Brown as a stunt double. Tiana reportedly was a choreographer, dancer and co-captain for Britney's tour, and was featured in "3" and "If U Seek Amy" videos.
Two pictures posted by ONTD feature Britney busting her moves in the middle of her backing dancers. The images don't show a clear view of Britney's face due to the "hair whipping" which hides her face from the camera. From those two angles, it seems that the female doing the routine indeed is not Britney, but there isn't any word from her camp concerning that matter.
Since the release of "Hold It Against Me", Britney has repeatedly been hit with harsh criticisms. When music video for the first single was debuted, the mother of two was slammed for filling it with advertisements and not dancing well enough.
At the celebration of "Femme Fatale" release, she was later attacked by music critics for her "lazy" routines when performing on "Good Morning America". Associate Director of Charts, Billboard Keith Caulfield said back then, "You expect her to dance ferociously. Because one can say, well you're lip syncing and when you're lip syncing, we expect you to dance."