It was John Lennon who wanted Phil Spector to produce the album. Spector worked on Lennon’s “Instant Karma” and was known for his bombastic “Wall Of Sound” style. McCartney hated the production of Spector, and in 2003 he pushed for the album to be remixed and released without the influence of Spector. The result was Let It Be … Naked, which eliminated most of Spector’s work and is much closer than The Beatles intended for the album. “Maggie Mae” and “Dig It” were eliminated, and a completely different guitar solo was used for this song.
You will hear different guitar parts in different versions of this song, since there were several overdubs of the solo. On April 30, 1969, George Harrison overwrote a new guitar solo on the best take of the session on January 31, 1969. Harrison overwrote another on January 4, 1970, but there is a possibility that it was actually McCartney in that overdubbing. The first overlay single was used for the original single version, and the second overlay single was used for the original version of the album. The version of Let It Be … Naked is that of the movie.
The Beatles were not the first to release this song, Aretha Franklin did. The Queen of Soul recorded it in December 1969, and was released on her album This Girl’s In Love With You in January 1970, two months before The Beatles released her version (she also covered The Beatles “Eleanor Rigby” in that album).