Recording for the album took place at Abbey Road Studios in London, beginning on 26 September. Lennon played guitar or piano on the songs, with bassist Klaus Voormann and drummer Ringo Starr as the other core musicians. The album title refers to the Plastic Ono Band, the conceptual band Lennon and Ono formed in 1969 of various supporting musicians they would use on their various solo albums. Lennon asked Phil Spector, who had produced Lennon's hit "Instant Karma!" earlier that year, to co-produce the new album. Since they were unable to contact Spector before recording began, Allen Klein, Lennon's manager, took out an advertisement in "Billboard" magazine that read: "Phil! John is ready this weekend."