The 70-year-old musician said that he and bandmate George Harrison were particularly amused by a furniture commercial, reported Contactmusic.
"There were millions of things. Information we'd had from very early childhood and from teenage hood, when you're going down the cinema, seeing something funny and making a song out of it," he said.
"George and I really loved cinema adverts. There was one for furniture called Link, showing this couple eyeing stuff up, where the catch phrase was, 'Thinking of Linking?' And me and George were like, 'You know what? That's a good title.' So one of my earliest songs went, 'Thinking of linking my love with you, thinking and linking can only be done by two.' Terrible! We never did anything with it, of course," McCartney added.