This was test footage for the kids are alright but it never got in there which is such a waste, they clearly are having a good time here.
 
Entwistle isn't seen but judging from footage that DID get into the movie from this jam he was playing his Alembic Exploiter bass.

I have to say that's high on the list of favorite tunes to perfrm at gigs.  Some musicians may consider it cliche, but it always gets the crowd rockin.