The song was recorded during the band's Magical Mystery Tour period, but remained unreleased until it was included on the Yellow Submarine soundtrack.

McCartney described the song as a children's sing-along with the title phrase inspired by the music hall tradition of asking the audience to join in.

[1] According to music critic Tom Maginnis of AllMusic, McCartney created the song "to match the same light-hearted spirit" of "Yellow Submarine".

[4] George Martin was absent from this session, leaving recording engineer Geoff Emerick in charge of the control room.

Paul McCartney performed the song live for the first time by any Beatle on 4 May 2013 at the Estádio Mineirão, Belo Horizonte, Brazil.