Dave Grohl’s baby mama may have upended the Foo Fighters frontman’s longstanding marriage — but she’s more than just a rock and roll groupie.

Jennifer Young, as confirmed by The Post, is the mother of the fourth child of the former Nirvana drummer. She holds a master’s degree from the producer’s program at UCLA, has professional experience as an on-set assistant to actor Justin Theroux, and has been involved in horror film projects alongside prominent industry figures such as Sam Raimi and Jason Blum. These details have been sourced from various interviews she has participated in.

She’s even co-wrote a graphic novel, “Cannibal,” described as an “anti apocalypse” story involving a “cannibal virus,” Young said in a interview.

Young, 38, gave birth to a girl Aug. 1, and Grohl, 56, vowed to be a “loving and supportive” parent to his fourth child.

Young, who is from Florida but now lives in LA, was born to a 15-year-old mother who fostered her love of horror movies, she told VoyageLA in 2021.

“I was watching Poltergeist, Pet Sematary and Candyman. I saw Pulp Fiction when I was eight years old from the front row of the movie theater,” she said.

She originally wanted to be an actress and said she bought a one-way ticket to New York and began auditioning, she told the outlet.

“What I ended up learning was that my passion for film was a passion for storytelling and I could do that in front of or behind the camera,” she told VoyageLA. “I wrote a comic book that was published with Image Comics and turned it into a pilot that is currently in development.”

Young was a hard worker with several producing credits but had been unable to land her big break in the film and TV industry, said a source who was close to Young a few years ago.

“She’s got a magnetic personality,” the source told The Post. “She’s funny. I’m a bit introverted – she’s extroverted. She’s not afraid to talk to people.”

The affair with Grohl was a shock, the source said.

“(I’m) disappointed more than anything – she was never somebody who I would imagine would be involved with somebody who was married. She was a faithful person as far as I knew her to be. That aspect of it was disappointing too,” the source said.

Only a few people close to Young knew she had a child with Grohl, said the source, who added she wasn’t even a big Foo Fighters fan and doubted she became pregnant intentionally.

“I think it probably was an accident,” he said. “I can’t imagine – she never struck me as someone that obvious. …She was an [average] fan. When you work with people – it probably just happened organically. It was probably just likely that it started as a friendship.”

It’s possible the pair met on the Foo Fighters 2022 horror movie, “Studio 666,” though Young is not listed in the film’s credits.

Young, who is living with her child and mom in a modest house in a leafy Los Angeles neighborhood, declined comment Friday when asked whether Grohl was living up to his promise to parent their daughter.

It’s unclear how much contact Grohl has with Young, who sports tattoos of Paul McCartney lyrics and the Metallica logo.

Young was in New York City on Valentine’s Day, at the same time the rocker was in town for Saturday Night Live’s 50th anniversary show but the pair haven’t been spotted together publicly.

Her identity had remained a mystery ever since Grohl revealed he cheated on wife of 21-years Jordyn Blum in an Instagram post last September.

“I’ve recently become the father of a new baby daughter, born outside of my marriage,” he wrote. “I plan to be a loving and supportive parent to her. I love my wife and my children, and I am doing everything I can to regain their trust and earn their forgiveness.”

Grohl is still his wife, but they have reportedly struggled since the news of the affair and love child.

Young’s former friend thinks she will land on her feet no matter what happens with Grohl.

“She was self sufficient,” the source recalled, recalling how in film school she took out loans for her education. “She’s a motivated, hard working person. Her ultimate goal was to write and direct and make movies.”

In a reflective moment during the 2021 interview, she talked about her career trajectory.

“As a filmmaker, being comfortable with the fact that your taste might always be a few steps ahead of where you are in your career. I may never make a film as good as Boogie Nights… but I’m damn sure gonna try.”

“Sometimes life’s lessons are learning who you DON’T want to be… and what you DON’T want to do,” she continued. “And that’s okay too.” Not every boss is going to be a mentor. I trust that these experiences will also pay off and shape me to becoming a better person to those around me. Know when to hold em, know when to fold em.”