During 1967 and 1968, the Beatles set aside several new recordings for their forthcoming animation movie, Yellow Submarine. Whilst the film was being completed, these tracks were assembled for inclusion on the film soundtrack and the accompanying LP.
This acetate includes rough mono mixes of the four new songs that appeared on the Yellow Submarine LP. All of them differ slightly from the versions released to the public. Only A Northern Song and Hey Bulldog each run a few seconds longer than on the record; while All Together Now opens with some extra bars of acoustic guitar, removed before the song was released. The most radical differences occur on the George Harrison composition, It's All Too Much. This early mix is more than two minutes longer than the released version, and features an entire verse that was heard on the film, but has never been included on an official Beatles record.
The Beatles originally intended to release these four songs as an EP, to coincide with the première of the film, but in the event they were issued on an album, alongside other music heard in the film.