Oh! Darling

"Oh! Darling" is a song of The Beatles written by Paul McCartney (credited to Lennon/McCartney) and is the fourth song on the "Abbey Road" album.
Background.
McCartney later said, "When we were recording 'Oh! Darling' I came into the studios early every day for a week to sing it by myself because at first my voice was too clear. I wanted it to sound as though I'd been performing it on stage all week."
In a 1980 interview with "Playboy" magazine, John Lennon said, "'Oh! Darling' was a great one of Paul's that he didn't sing too well. I always thought I could have done it better—it was more my style than his. He wrote it, so what the hell, he's going to sing it."
George Harrison described the song as "a typical 1950s–'60s-period song because of its chord structure."
"Let It Be" session.
After an early attempt at this song on 27 January 1969 during the "Let It Be" sessions, Lennon announced, "Just heard that Yoko's divorce has just gone through", after which he and the band burst into an improvised version of the song, singing "I'm free at last" instead of a part of the lyric.