“ ‘Yesterday’ feels like a shift in the balance of power,” says Leslie. “From the beginning they were equals, and ‘Yesterday’ wasn’t only just a hit, but the song that more artists covered than any other Beatles song. Paul even sang it onstage by himself when they performed. And it triggered John’s insecurities.”

Paul McCartney and John Lennon had a private conversation when George Harrison briefly left The Beatles. Secretly recorded by the Let It Be filmmakers, one moment saw an earth-shattering confession that is something fans have always suspected.

John Lennon and Paul McCartney penned some of the biggest hits in the history of music but they didn't always see eye-to-eye and were both critical of each other's work