Sir Ringo enlisted the help of Sir Paul, 77, to play bass on the track, which he admitted had brought him to tears when he first heard it.
He said: “Jack asked if I ever heard The Bermuda Tapes, John’s demos from that time. And I had never heard all this.
“The idea that John was talking about me in that time before he died, well, I’m an emotional person.
“And I just loved this song. I sang it the best that I could. I do well up when I think of John this deeply. And I’ve done my best. We’ve done our best.”