Mick Stadium has uploaded another super rare clip to his Youtube channel: John Entwistle on the Old Grey Whistle Test in 1973. I may be wrong, but this seems to be the first time it has appeared on the Interweb.

1973’s “Rigor Mortis Sets In” was John Entwistle’s third solo release. LP featured classic covers, new versions of Entwistle songs and then-new recordings.
LP was recorded in less than three weeks and cost only $14,000 to make (with nearly a third of the total cost spent on liquor.)

Sounds like a better-than-average Who song.