Allison Kyler

Multiple sources close to production of Britney Spears' music video for her new single, Hold It Against Me, are claiming that the pop star was unable to keep up with the fast-paced dance routine, and director Jonas Akerlund ultimately got so upset that he asked her dance-double, Allison Kyler, to step in - leaving Brit Brit in tears! ...

Source: http://perezhilton.com/2011-02-02-britney-spears-allegedly-uses-dance-double-in-hold-it-against-me-music-video