Yoko Ono walked into the office of her assistant, May Pang, one day in 1973 and explained that she and John Lennon weren't getting along. He intended to see other people, so Ono told Pang she'd like her to go out with him.

Pang, who was 22 and had been working as the couple's PA for a few years, was shocked. She staunchly resisted the idea at first but eventually became Lennon's lover when he was separated from Ono, a period that's come to be known as his "Lost Weekend."

In the new film The Lost Weekend: A Love Story, Pang is asked what happened that made her change her mind. "John," is her simple answer.

Even though Lennon struggled with his drinking, in the roughly 18 months he and Pang spent together, the former Beatle came into his own in a way he never had before. He collaborated with Ringo Starr and George Harrison on Starr's "I'm the Greatest," landed two hit singles on his 1974 album Walls and Bridges ("Whatever Gets You Thru the Night" and "#9 Dream), produced the Pussy Cats album for drinking buddy Harry Nilsson, co-wrote the No. 1 "Fame" with David Bowie and rekindled his relationship with his son, Julian.

Pang was there for it all. She witnessed Phil Spector reportedly fire his gun in the control room, inches from Lennon's ear, watched up close when Lennon performed live for the first time in years with Elton John at Madison Square Garden and sat nearby while Lennon, on vacation in Disney World, signed the paperwork that officially ended the Beatles. She even took the last known photograph of Lennon and Paul McCartney, relaxing in the sun in Santa Monica, Calif., in 1974.

Lennon and Pang broke up in 1975, and Lennon reconciled with Ono. Since then, Pang has regularly spoken about their relationship, releasing the 1983 book Loving John: The Untold Story, on which the new documentary is based. Ahead of the film, which opens in theaters on April 13, Pang tells UCR about her time with the late Beatle.

At the beginning of the film, you talk about growing up in Spanish Harlem and being drawn to rock 'n' roll bands, including the Beatles. Do you remember your very first impression of them?
Oh, the first time I heard about them ... I kept thinking, Who's this band that's just thrown the Beach Boys and the Bobby Rydells and the Frankie Avalons of the world at that point? And you start thinking, 'Oh, OK.' And then when they appeared on Ed Sullivan, it was like a game changer. Just watching them was so different. It was so refreshing. I loved their look, you know, their long hair ... they had that sense of humor, which we hadn't seen. And they had it, they had it all.

And did you continue to be a Beatles fan through the years? 
Oh, absolutely. You know, I still have my records [from] when I bought them back then when I was 13. You sort of sit there and you go, 'Oh, my God, I still have this.' I do remember kids in school making fun of me because they said, 'Oh, they're just a fad. They'll be over in six months.' And I was so adamant. I said 'It's not, it's not, it's not.' Well, I guess I proved them wrong.

Watch a Trailer for 'The Lost Weekend: A Love Story'

When you were working on this film, was there anything that surprised you?
There's still things that could be done. ... The film is 96 minutes, including credits. You don't want it to go longer than that, and you can only put so much in that time frame. And I was surprised that they found as much as they did on me, because the fact is, back then ... I tried to stay out of the way. I always used to say, 'There's only one star in the household and it isn't me.' ... And when I saw the movie, I thought, 'Where did you get that photo? I've never seen this.'

What do you wish more people knew or understood about John Lennon?
I think the myth to all of this - a lot of it is that he was drunk all the time during our time period. And he wasn't. Because we keep repeating the same story over and over that it sounds like he was drunk the whole time we were together, and that is not the truth. ... It's just that he got the copy. I always [said], if you go out to do this, who's going to make better copy? Harry Nilsson or John Lennon? Who's going to make the better news story? So John always got the press more than anybody else. And it was a very misunderstood time. And John loved working, and he was working all the time. You can't be drunk when you're working all the time.

You've explained over the years that you were not initially receptive to Yoko Ono's idea. But looking back now, with 50 years of hindsight, are you glad things turned out the way they did?
Well, you know, the only thing that I feel sad about is that John and I didn't continue in that sense. We didn't continue as a couple. But who knows? And I will never know. ... When you go back into looking at things, you say, 'Could I have done anything better?' We could always do better. Would that have been what the universe wants? No, maybe not. I think I fell into the path the way it's supposed to be for the time being ... it's up in the universe as I would say.

Is there anything else you'd like people to know about the film? 
I think they'll be surprised. ... The tagline is always: I know your story. And when they go and see it, they go, 'I thought I knew your story. I didn't know a lot about your story.'

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