The Beatles sang about “Lucy in the sky with diamonds.” But for one of the Fab Four, it was George in the back room with Rubies at iconic New York rock club Max’s Kansas City.

The new documentary “Nightclubbing: The Birth of Punk Rock in NYC” – which will be screening at Joe’s Pub on Tuesday, Wednesday and July 30 — reveals George Harrison had an incredible way of picking up chicks in Max’s VIP back room.

“He always carried a little ruby ​​pouch,” Max legend Alice Cooper recalled in the doc. “And once he decided who he wanted to be with, he would put the ruby ​​in front of her.” And if she picked up the ruby, that was a done deal then.

“Nightclubbing” – which premiered at the Dock of the Bay Film Festival in San Sebastián, Spain, in May – takes you to the heart of the sex, drugs and rock ‘n’ roll that took place in Max’s Kansas City in the burgeoning thrashing of the punk-rock movement with New York artists such as the Velvet Underground, the New York Dolls and the Ramones. Not just a punk mecca, it was also where Bruce Springsteen and Aerosmith were signed by Clive Davis, and where Debbie Harry served new-wave attitude as a waitress before forming Blondie.

“That was the cool factor,” Cooper said. “There were lots of other little places to play, but Max’s was the place. It was the cool place.

“It was one of the houses of punk,” added Billy Idol. “That’s what it was for us.”

Restaurateur Mickey Ruskin opened Max’s Kansas City at 213 Park Ave. South in December 1965, eight years before the more heralded CBGB. With a restaurant up front and a back room for VIPs, it transformed into a hipster hangout when Andy Warhol became a regular with scenes from his neighboring studio, the Factory.

Models and movie stars – from Warren Beatty and Jane Fonda to Jack Nicholson and Elizabeth Taylor – mixed and mingle in the bustling back room. “It was a great place to hang out,” Cooper said. “There was no one there trying to get your autograph, because everyone was taller than you.”

Max added live music in 1969, featuring artists such as the Stooges. Cooper recalls a particularly piercing performance from the Stooges frontman Iggy Pop, who, bloodied from rolling over glass on stage, had to suffer 16 stitches afterwards. “I think [Stooges manager] It was Danny Fields and I who took him to the hospital,” he said.

It was also at Max’s that Iggy Pop met David Bowie, sparking their renowned creative collaboration, while Ziggy Stardust also drew inspiration from Cooper and his eponymous band for his Spiders from Mars backing band.

In the early 70s, when Max’s was becoming a real concert hall with its room upstairs, there was a lot of debauchery. It was not uncommon to find people having sex in the bathroom or injecting amphetamine into their buttocks.

“It was all about sex and drugs,” said trans punk rocker Jayne County.

County also recalled Dee Dee Ramone revealing his scarred penis after he was attacked during an altercation with his girlfriend. “She freaked out and tried to stab Dee Dee in the c–k, and tried to cut her c–k,” she said. “And he had scars on his ck.”

“Nightclubbing” also chronicles how Sid Vicious played his last gig at Max’s in 1978, 12 days before his girlfriend Nancy Spungen was found dead at the Chelsea Hotel. Vicious was arrested for her murder but never stood trial, as he died of a heroin overdose while out on bail.

Idol fondly remembers playing closing night at Max’s Kansas City in 1981, performing “Dancing With Myself” among other songs. “It was my way of saying thank you… cementing myself a bit with the Max’s story in a way,” he said.