Having only recently returned to producing, after the commercial failure of Ike & Tina Turner's 1966 single "River Deep – Mountain High" in America, Spector had "passed the audition", according to "Beatles Forever" author Nicholas Schaffner. "Instant Karma!" was the first of many Beatles-related recordings that Spector worked on during the early 1970s. Lennon and Harrison were sufficiently impressed with his production on the song that they asked Spector to work on the tapes for the Beatles' final album release, "Let It Be", and then to produce their respective 1970 solo albums, "John Lennon/Plastic Ono Band" and "All Things Must Pass".