This is an unaired opening song-and-dance little number that Craig Ferguson did for all the non Doctor Who fans of his Late, Late show, that was supposed to air on November 16th when Matt Smith guest-starred on the show.
That opening segment wasn't cleared by the BBC and Ferguson was apparently pretty pissed at this. But now, it has finally made it online for all to see. And it's frakin' hilarious!
Thanks to The Real Rebel for the heads up!