Leary and his wife Rosemary were invited up to Montreal, where John and Yoko were between the sheets for another major "bed in" on the 19th floor of the Queen Elizabeth Hotel. They arrived on June 1, 1969, and were promptly roped in to singing on the chorus of Give Peace a Chance, which was recorded in the hotel bedroom. Leary and his wife were rewarded for their participation by having their names included in the lyric.

The next day, John asked Leary if there was anything that he could do to help him in his campaign, and was asked if he could write a song to be used in commercials and performed at rallies. Leary's slogan was "come together, join the party" — the "come together" part originating in the I Ching, the Chinese book of changes. "There was obviously a double meaning there," said Leary. "It was come together and join the party — not a political party but a celebration of life."

John immediately picked up his guitar and began building on the phrase: "Come together right now, Don't come tomorrow, Don't come alone, Come together right now over me, All that I can tell you, Is you gotta be free." After coming up with a few more versions along the same lines, he made a demo tape and handed it to Leary.

Leary had the song played on alternative radio stations throughout California and began to think of it as his own. However, unknown to him, John had returned to England and within seven weeks had recorded a version with the Beatles. In October, it was released on the flip side of Something, the first single to be taken from Abbey Road.

Leary's campaign to become governor of California came to an abrupt halt in December 1969, when he was charged with possessing marijuana and eventually imprisoned. It was while in prison that Leary first heard Abbey Road on a local rock station and, no doubt, Come Together came as something of a surprise. "Although the new version was certainly a musical and lyrical improvement on my campaign song, I was a bit miffed that Lennon had passed me over this way ... When I sent a mild protest to John, he replied with typical Lennon charm and wit that he was a tailor and I was a customer who had ordered a suit and never returned it. So he sold it to someone else."

The recorded version, with its semi-nonsense lyric, was largely made up in the studio, the swampy New Orleans bass having been added by Paul. Two of the song lines referring to "old flat top" were lifted from Chuck Berry's You Can't Catch Me and John was later sued for plagiarism. It was hard to deny where the words had come from, although in this new context they were nothing more than an affectionate nod towards the music of his youth. John strenuously denied any musical theft.

The conflict was resolved when John promised to record three songs belonging to the publisher of You Can't Catch Me. He fulfilled this promise when he recorded Berry's Sweet Little Sixteen and You Can't Catch Me for his Rock' n 'Roll album and Lee Dorsey's Ya Ya on Walls And Bridges.

Come Together was released as a single in October 1969 and topped the American charts. Teamed up with Something as a double A side in Britain, it only reached No 4.