Steeleye Span with Peter Sellers: New York Girls

What was Peter Sellers doing playing the ukulele on a track on Steeleye Span's 1975 album Commoners Crown? 

Maddy Prior explains:

While sitting over lunch we were discussing what we need to sparkle up the track New York Girls. Ukulele would be good someone said. Anyone got one? Anybody know someone who can play one? Peter Sellers plays it says Bob. Pause. Eyes meet, why not? We could ask. He could only say no. 

So we spent another interesting afternoon with a rather diffident Peter Sellers. I don’t think he’d ever been asked to play on a session before and was apprehensive about the whole affair until he realised we were delighted to have him there. He loosened up as time went by and finally finished by adding, unprompted, some Goon voices. We were ecstatic.

Bluebottle writes: I like this game!