Anyway, this track you're hearing in this video comes from Girl Talk's last album, All Day. I reviewed it over here. It was pretty sweet, if I remember correctly.
So, yes, the song is old, but the video is new, and it's the start of what is going to be a pretty ambitious video series revolving around this Girl Talk album. It involves three different dancers performing in various places around New York City, and they look like they're having a ton of fun doing is--especially that ballet girl.