The one thing about ballet that seems predominant anytime you see it is the consummate professionalism of everyone involved. Usually, it is a well choreographed, well oiled machine. But such is not the case of one background dancer that someone caught on tape during the performance you are about to see.
Seems this person was getting a little into it, and ballet moves was turning into funk moves real quick. It may start slow, but watch the dancers in the back and you will figure out pretty quickly who to keep an eye on.
Just a little back story so it makes more sense. It was a performance for Moscow children, and the background dancers are allowed to get a little more "hip" so the kids don't get bored. How awesome is that?