Paul McCartney surprised by his own role

In 1964, in the midst of Beatlemania, everything the Beatles touched turned to gold. Even Paul McCartney was surprised.
There was a song written by the band’s bassist that they released as part of an album that was more successful than they expected.
When The Beatles released A Hard Day’s Night, it was clear that it would be a hit as an album. But one song, even though it wasn’t even a single, managed to do better than the others.
This is the one that appeared on the soundtrack of the movie “All My Loving”, even though it only lasted a few seconds. But then it gained its own fame.
The story of how this Beatles song became popular was told by Paul McCartney. “You know, it was on this album and the first person to play it as a single was DJ David Jacobs, it was quite modern.
“I remember him featuring it on his radio show and I think from then on it became a big favorite of people. And I listened to it differently, I had heard it as part of the album by then. But when he put it on the radio program and it reached millions of people on the BBC, I was like ‘Wow! That was good’ I’ve always loved it,” added the former Beatle.