MARK ANATER ...
The question apparently refers to I Me Mine. Although all of the songs on the Let It Be album received the Phil Spector treatment after the fact, I Me Mine wasn’t actually recorded until a year after the others, and had no contribution from John Lennon.
George Harrison brought the song into the Get Back/Let It Be rehearsals in January 1969. He had just written the song, inspired by the power struggle he was witnessing between John Lennon and Paul McCartney, and the divisiveness caused by Yoko’s presence. He was also chafing more than ever at the highhanded attitude of Lennon and McCartney toward the songs he wrote. I Me Mine was no exception.
Harrison first played it for Ringo ahead of the day’s rehearsals. He, McCartney and Ringo ran through it, while Lennon mocked it and declined to participate, at one point picking up Yoko and dancing a waltz with her.
All of this was captured on film, as the rehearsals were supposed to be part of the whole project of interrelated album and movie. When the project was finished, however, no one was happy with the results, and the tapes and film were shelved.
Months later new group manager Allen Klein revived the project, and director Michael Lindsey-Hogg assembled a rough cut of the film which included the I Me Mine rehearsals. It was only then that everyone realized the band had not made a proper studio recording, so a session was hastily scheduled for 3 January 1970.
Lennon had announced his “divorce” from the band over three months earlier, and was not even in Britain at the time, as he and Yoko were on holiday in Denmark. There was zero chance he would do it even if he were there, so the other three did it without him. Phil Spector later added orchestration and choir, plus a drum overdub by Ringo that counts as the final track ever recorded for a Beatles song.