John Lennon began doing a Jerry Lee Lewis impersonation while onstage. His performance made George Harrison laugh so hard he couldn't play guitar.
During one of The Beatles’ most stressful concerts, John Lennon managed to make George Harrison laugh onstage. He began behaving in such an outrageous fashion that all of his bandmates took note. According to Lennon, his joking was so successful that Harrison couldn’t play his guitar.
The Beatles’ concert at Shea Stadium in New York was their largest up until that point. They were incredibly nervous before taking the stage. Once they did, though, Lennon began to behave comically. He did a Jerry Lee Lewis impression and began playing the piano with his feet. Harrison found all this hilarious.
“I was putting my foot on it and George couldn’t play for laughing,” Lennon said in The Beatles Anthology. “I was doing it for a laugh. The kids didn’t know what I was doing.”
Source: Emma McKee/cheatsheet.com