May Pang was set up with ex-Beatle John Lennon by Yoko Ono

May Pang was almost the Yoko Ono of Yoko Ono’s marriage.

The then-22-year-old was working as an assistant to Ono and John Lennon when, at Ono’s own request, she reluctantly became Lennon’s girlfriend in 1973.

As Pang remembers Ono putting it, “He needs someone nice, like you.”

But Ono was likely not expecting things to go as well as they did, or for Pang to almost break up her marriage to the former Beatle.

Looking back, Pang — a lifelong Beatles fan and subject of the new documentary “The Lost Weekend: A Love Story,” in theaters April 13 — told The Post, “It’s almost surreal. In one way, Yoko took advantage because I was naïve. But she also gave me a gift. John and I fell in love.”

Beyond the expected sexual liaisons, their time together included gunplay, stoned-out jam sessions, Paul McCartney playing spy for Yoko, drunken carousing through the nightclubs of Hollywood, and at least one house trashing.

It began in 1969 when 19-year-old Pang fluked into a job as an office assistant for Apple Records, the Fab Four’s label.

“I asked if the Beatles ever come here,” Pang, now 72 and living in Queens, recalled. “[The office manager] just chuckled and said, ‘No.’”

But he was wrong.

In 1970, Lennon and Ono relocated from London to New York and visited the office. “Apple’s VP said to me, ‘Get your ass upstairs and see what they need,’” Pang recalled.

What they needed was an assistant. Pang landed the gig.

It was heady work for a first-generation Chinese American who grew up in Spanish Harlem and, previously, had gotten no closer to rock stars than dancing to their records.

Early tasks included procuring flies from restaurant dumpsters for Ono’s art film “Fly.”

The footage captured actress Virginia Lust, allegedly sedated, as some 200 flies, shown one at a time, exploring her body.

But the most outrageous assignment came from Ono in 1973.

It seemed like a typical morning in the couple’s Manhattan apartment at the Dakota building when, Pang told The Post, “Yoko said, ‘John and I have not been getting along. He is going to start going out with other people. I think you will be good for him.’”

Astonished, Pang protested. She did not want to be the girlfriend of her married, 32-year-old boss. “Yoko said, ‘You should [do it].’ Then she walked out of the room,” Pang recalled.

She did not know it at the time, but, she now believes, “Yoko wanted me to be his girlfriend so she could control the relationship.”

With neither Pang nor Lennon naturally interested, the arranged romance started slow.

After a week Lennon stole a kiss from her in the Dakota elevator. “A week later, he got to second base,” she said. “Days after, he hit a home run.”

As for the quality and frequency of the sex, she euphemistically says in the documentary, “It was cock-a-doodle-do all the time … John Lennon charmed the pants off of me. After we made love [for the first time], I started to cry.”

Things accelerated in September 1973. Early one afternoon, Lennon said, “We have to get out of New York, May. Just the two of us. Away from Yoko.”

By 6 p.m. that day, they were en route to LA.

So began an 18-month-long affair that has come to be known as John Lennon’s Lost Weekend.

“We fell in love with each other,” said Pang. “We were like a couple of kids. His favorite thing was to go to IHOP and eat blueberry pancakes.”

They moved into a Bel-Air mansion, on loan from legendary record executive Lou Adler (Carole King, the Mamas, and the Papas).

Life was idyllic.

Pang photographed Lennon continually (an exhibit of her Lost Weekend era photos runs April 8 and 9 at City Winery).

They wore each other’s clothing and rubbed elbows with LA royals such as Warren Beatty, Cher, and Elizabeth Taylor.

For Pang’s 23rd birthday, in October 1973, Lennon bought her an orange Plymouth Barracuda.

He drew pictures that showed her speeding, as he sat in the backseat, screaming, “Help.”

But there was also a wild side. Unbound from Ono’s sensible restraints, Lennon hit Tinseltown hard — and not always to the best effect.

“It was a rehash of my youth,” Lennon once said. “Acting like a teenager in Hollywood.”

On one occasion, he drunkenly turned up at a hot LA nightclub called the Troubadour with a tampon tied around his head.

According to the Guardian, he proceeded to “make a supreme fuss at the ticket counter” for comped drinks — and stiffed the waitress who called him “some jerk with a Kotex around his head.”

Another night at the Troubador, things got wild when Lennon and his pals were smashed on Brandy Alexanders.

“It was a comeback show for the Smothers Brothers [a comedy duo canceled by CBS due to off-color humor],” recalled Pang, who did not drink alcohol. “We were at a table with Pam Grier, Peter Lawford, and Harry Nilson [a hell-raising musician whose 1974 “Pussy Cats” album Lennon produced].

“Harry heckled the Smothers Brothers and got John to join in. All of a sudden, the Smothers’ manager came over and grabbed John by the collar. John didn’t like it and the table went flying.”

Lennon and Nilson were shown the door.

Prior to the dust-up, Lennon showily made out with Pang.

Photographers had a field day.

Back in New York, Ono was keeping tabs on the relationship.

“She’d call 20 times a day,” said Pang. “Sometimes it would be at 4 a.m. And the calls were over nothing. She would say, ‘I just went for a walk.’ I would say, ‘And?’ But there would be no and.”

According to the doc, Ono even had a hand in a surprise reunion between Paul McCartney and Lennon in LA.

“John was not responding as Yoko wanted,” said Pang, meaning that she hoped Lennon would tire of Pang and return to her. “She called on Paul to see what was happening with us. She told Paul, ‘Oh, I don’t mind John coming home.’ John never knew, but Yoko sent Paul to check us out.”

While life in LA was not all play — Lennon recorded his album “Rock ‘n’ Roll” during this period, with notorious producer Phil Spector — even efforts to work skidded off the rails.

“Phil liked poppers,” Pang recalled, referencing capsules of alkyl nitrate that were snapped open and caused a quick high via inhalation of the fumes. “And he popped them under everyone’s nose. He was a nightmare.”

Pang told The Post that the craziest Spector session ended with him shooting a gun in the studio lounge while chatting with Lennon.

“Everybody hit the ground; I ran toward the gunshot,” said Pang. “I entered the lounge and heard John say, ‘If you’re going to shoot me, shoot me. But don’t f–k with my ears. I need them.’”

That night, back at Adler’s house, following a drunken scuffle with Spector and Spector’s bodyguard, a vodka-blasted Lennon flipped.

“He threw a chair through the window and broke a gold record,” said Pang. “The next morning, John told me that they took his glasses and tied him up with Lou’s neckties. He didn’t know his whereabouts. Phil’s bodyguard sat on him. John thought there was going to be an all-male ménage à trois.”

After about six months in LA, the couple returned to New York — but not to Ono, Pang said.

“John was with me. We moved into a one-bedroom apartment on East 52^nd Street. It’s where Bob Gruen shot the famous photo of John on the roof, wearing a T-shirt that said ‘New York City.’ I took a photo of Bob taking the photo,” she remembered

They lived as an unabashed couple and Lennon, according to Pang, made his preference for her clear.

At an off-Broadway premiere of a musical based on “Sgt. Pepper’s Lonely Hearts Club Band.” Ono turned up and Pang recalled that she “whispered to John, ‘Do you want me to give up my seat?’ He bluntly said, ‘No! Let her sit in the back.’”

Then things became serious: “In January 1975, after visiting Mick [Jagger] and Bianca [Jagger] at Andy Warhol’s house in Montauk, we found a house to buy there. I think Yoko got wind of how close we became. If we bought the house, it would have been the end.”

Later that month, on a Friday night, Lennon went to the Dakota.

Ono had set up an appointment with a hypnotist, ostensibly to help him quit smoking.

“He headed it for the door and I knew it was not good,” said Pang, adding that Lennon promised to come back but spent the weekend with Ono. When they reconvened on Monday, Pang said, “John told me, ‘Yoko is allowing me to come back.’ I asked whose idea it was. He said ‘Nobody’s.’ That was the end. It hit me hard.”

Pang soon ceased working for Lennon and Ono and secured a job at Island Records. Still, over the next five years, there were phone conversations and sexual intimacies between her and Lennon.

“Calls would be sudden,” said Pang. “The last one was on Memorial Day Weekend 1980. He called from Cape Town and said, ‘We have to find a way for us to get together.’”

Some six months later, Lennon was fatally shot by Mark David Chapman in front of the Dakota.

“I was at a friend’s house and heard on the radio that John was shot,” Pang said. “I went cold and called a friend to make sure I heard it correctly. I next heard that he was dead. I dropped the phone and screamed. I later spent a lot of time crying by myself and spoke with him spiritually. I’d say, ‘I can’t believe you’re not here.’ We never had closure, and I don’t have closure to this day.”

Though Pang has mostly been out of touch with Ono since the Lost Weekend, she heard from a mutual friend, the late ’60s radical Jerry Rubin, how Ono really felt about her backfired plan.

“Jerry told me Yoko was surprised my relationship with John lasted more than two weeks,” said Pang, who has two children with her former husband, music producer Tony Visconti. “Her plan was for it to really be a lost weekend. But it wasn’t that. She did not expect us to fall in love.”