We never see this may classic rock stars performing at once. A classic. On stage direction by E.C. Smith, you can see him directing if you watch closely. He's the one with the 'bowl' haircut. At the 2 minute mark watch him separate McGuinn and Dylan and gives the nod and grins to Clapton to do his riff. Later he steps up and directs Young to the mike for his solo part. E.C. led the Saturday Night Live band for several years. When Harrison is singing E.C. has quite a look on his face. He knows he is in the middle of directing the best rendition of My Back Pages ever, and surrounded by stars bigger than he will ever be.