Mary McCartney Says Dad Paul Gave 'Little Tips' for Abbey Road Documentary: He's 'Passionate'

For some children, spending time in their parents' place of work can be a drag. For Mary McCartney, though, going to work with mom and dad meant spending time in one of the most legendary recording studios of all time: Abbey Road Studios.

It makes sense, then, that it's McCartney, daughter of Beatle Paul McCartney, who is bringing the London locale's storied history to the silver screen in her new documentary If These Walls Could Sing, which will hit Disney+ on Dec. 16.

"I had no idea that it was 90 years old. I've grown up going my whole life, but I never knew all the facts," the photographer, filmmaker and cookbook author, 53, told PEOPLE at the film's Wednesday night premiere in N.Y.C. "So I've really immersed myself in it and really dissected the stories and I think there's some surprises in there."

McCartney first felt moved to begin work on the project after she spotted a 1977 photo of her parents, Paul and his first wife Linda McCartney, strolling through a nearby crosswalk with a pony in tow.

Karwai Tang/WireImage Paul McCartney and Mary McCartney

"I love the picture of my mom going over the zebra crossing. She had a little pony in London. That's one of the reasons I wanted to do [the film]," she said. "I snuck her into it a few times. There's an homage to her. She's my inspiration."

Though Linda died of cancer in 1998 at age 56, McCartney was able to get dad Paul, 80, on board, who shared with her the sort of insight only a former Beatle like himself could know.

"I was with him and I was like, 'I'm going to make this documentary about the history of Abbey Road,' and he would just sort of give me little tips. It was good! He was mulling it over and he sort of told me little anecdotes," she said.

RELATED: Paul McCartney, Elton John and More Revere Abbey Road Studios in Doc Trailer: 'It's a Gift to Music'

The star recalled one interview in particular with the "Band on the Run" singer, and said he was eager to talk not only about the studio itself, but about the people who worked there.

"He was keen to talk about how the people there had helped them—staff, people behind the scenes, engineers," she said. "He feels passionate about it. I think in the documentary you see how passionate he is about it."

ANGELA WEISS/AFP via Getty Mary McCartney

Though McCartney said she put most of the "juicy stuff" in the documentary, there were some fun details left on the cutting room floor — like the ways in which Linda found some unexpected benefits in Abbey Road.

"It was somewhere where I grew up, and my mom apparently would come around and be like, 'Could somebody babysit the kids tonight?' That kind of thing," she said. "It shows how I grew up there."

The studio has famously played host to everyone from The Beatles and Little Richard to Pink Floyd, the Spice Girls and Lady Gaga. In more recent years, it's also become a destination for film scoring; movies like Black Panther and many of the Star Wars and Harry Potter scores were recorded there.

If These Walls Could Sing incorporates vintage footage of artists recording, as well as new interviews with McCartney, Elton John, Ringo Starr, Noel Gallagher, Roger Waters and more.