In the late evening of May 30 1969 as John and Yoko were holed up in room 1742 of the Hotel Reine Elizabeth in Montreal, John grabbed his acoustic guitar and taught a few other people in the hotel room including Tim and Rosemary Leary.
Derek Taylor contacted EMI Canada and was sent a mobile recording unit through independant engineer/producer Andre Perry, a local. Andre brought up a four track Ampex that he had rented from RCA and arrived at the hotel room the next night (May 31 1969). While the recording and filming equipment was being prepared for the event, John and Yoko ran through the song with others in the room including Tommy Smothers, Timothy Leary and Rosemary Leary, Derek Taylor and some Krishna devotees.Rabbi Abraham Feinberg, Allan Ginsberg, Murray the "K" and others.Tommy Smothers played the second acoustic guitar and the Krishna people supplied some percussion.
After a couple of rehearsals with the singalong and John instructing the gang to "clap on the off-beat" - which is the two and four if you are musical - the recording used was taped at 11 in the evening with four microphones - two for the guitars and main vocals and two for the room crowd and ambience.
On June 01, Andre Perry took the tapes and transferred them from 4 track to 8 track. He had some session players sing along on the chorus and added a thumping drum beat to the song. Also, the tune was sped up a bit on the commercial releasse.
The song reached number 2 in the UK and number 14 in the us when it was released as an Apple single in 1969 along with Yoko's "Remember Love". The US release does not have a count-in. The original mix from the hotel room attributed to the promo film can be heard on the bootleg vinyl "The Lost Lennon Tapes Volume Twenty-Four".