what musical instruments are played in the background?
Piano, bass guitar, drums, etc.
Imagine (John Lennon song)
The finished recording featured Lennon on piano and vocal, Klaus Voormann on bass guitar, Alan White on drums and the Flux Fiddlers on strings. The string arrangement was written by Torrie Zito.

information about the song imagine by john lennon Lennon said that much of the song's lyrics and content came from his wife Yoko Ono. who wrote the lyrics of this track? John Lennon and Yoko Ono. what do these lyrics specify? Its lyrics encourage listeners to imagine a world at peace without the barriers of borders or the divisions of religion and nationality and to consider the possibility that the whole of humanity would live unattached to material possessions.
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Imagine (John Lennon song) [SEP] Recording and commercial reception
Put your political message across with a little honey." In an open letter to Paul McCartney published in "Melody Maker", Lennon said that "Imagine" was "'Working Class Hero' with sugar on it for conservatives like yourself". On 30 November 1971, the "Imagine" LP reached number one on the UK chart. It became the most commercially successful and critically acclaimed album of Lennon's solo career.