However, in a 1964 interview he said that he and Paul McCartney wrote it in the back of a van, declaring McCartney a contributor. Bootlegs exist of Lennon's original demo of the song, which was recorded on 31 May 1963.
In a 1964 interview, John Lennon claimed that he and Paul McCartney wrote the song while in a van, acknowledging McCartney as a co-writer.  Bootleg recordings exist of Lennon's initial demo version of the song, which was recorded on May 31, 1963.