Must be part of the show, there are other links of him in the "attic" with them. Cool clip! He's really dependent on the music sheet in front of him...
I can't watch the clip at home but I know what you're talking about. One of the people is Rachel Fuller, his long time companion. The other, more spastic, guy is Mikey Cuthbert, who gets a little too, um, enthusiastic shall we say.