If you are looking at the screen he is the guy with the guitar and microphone on the left.
So cool. He will be with her on Leno tonight and I think Kelly Ripa on Thursday. And something else I can't remember. Makes me miss my sister and him while they live out in CA. But hopefully we get to go see them in March as a family of 4. When I told Matthew that Uncle Jon was going to be on TV he started to dance. So cute.