Nothing brings out the best in a songwriter like a partnership with just the right amount of creative tension. Just ask Paul McCartney, whose long friendship — and rivalry — with John Lennon produced some of the greatest songs in rock 'n' roll history.

McCartney looks back on their complicated relationship in an excerpt from Paul du Noyer's new book, Conversations With McCartney, printed in the current issue of MOJO. As McCartney tells it, the competition between the two kept going well beyond the breakup of the Beatles, and may have even been responsible for spurring Lennon back into action after the five-year hiatus that followed his "lost weekend" period.

As McCartney tells it, Lennon was inspired to record his Double Fantasy album after hearing McCartney's 1980 single, "Coming Up." "Apparently John heard it when he was in New York," he recalled. "I saw a John documentary and somebody was saying, ‘I brought this record of Paul’s to John and played it for him.’ John went, ‘Oh f---in’ hell, the bastard’s done something good! I’ve gotta work!’ I love the idea of forcing him up off his arse."

Forcing one another up their respective arses, says McCartney, is something they had done since their earliest days. "I like that, because we were always doing that with each other," he added. "People sometimes see it as an arch rivalry. It wasn’t. It was a friendly competition that was actually very necessary."

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