Upon finding out from Pete Townshend that bassist John Entwistle could play trumpet, the band's manager, Kit Lambert, decided to allow the band to try creating a song featuring Entwistle's horns: When we recorded our first LP and wanted a bit of a different sound, Pete told our manager, Kit Lambert, that I could play trumpet.

[2]"Circles", backed with "Instant Party Mixture", was originally planned for release as the follow-up single to the band's smash hit "My Generation", on the Brunswick label, in February 1966.

[2] However, the band secretly broke their contract with producer Shel Talmy soon after the January recordings, and re-recorded the song as the B-side to their new UK single "Substitute".

The following week, Substitute was back on sale with the now named "Waltz for a Pig", the instrumental by the Graham Bond Organisation on the B-side, credited to the Who Orchestra.

He took it to the high-court judge and he said things like 'And then on bar thirty-six I suggested to the lead guitarist that he play a diminuendo, forget the adagio, and play thirty-six bars modulating to the key of E flat,' which was all total bullshit – he used to fall asleep at the desk...[4]After the ban was lifted, all three versions of the single – with "Circles" / "Instant Party" on the B-side as well as the new "Waltz for a Pig" – could be found in stores.

The song "Instant Party Mixture", which was originally meant to be the B-side to "Circles", was finally released as a bonus track on the 2002 reissue of the My Generation album.