The song is sung by a young man to his lover, and is about his plans of growing old together with her. Although the theme is aging, it was one of the first songs McCartney wrote, when he was sixteen. The Beatles used it in the early days as a song they could play when the amplifiers broke down or the electricity went off. Both George Martin and Mark Lewisohn thought that McCartney may have thought of the song when recording began for "Sgt. Pepper" in December 1966 because his father turned 64 earlier that year.