Dave Grohl has a reputation as a sweetheart, a two-time Rock & Roll Hall of Famer chummy with everyone from Paul McCartney to Nandi Bushell, the 12 year old Zulu-Brit musical phenom he lost a recent online drum battle to.

The former Nirvana drummer and leader of the Foo Fighters is the talking head most likely to turn up in the rock doc of your choice, and the mensch known to leave a $1,000 tip at a bar after ordering one drink.

He’s Dave Grohl, the nicest guy in rock and roll.

So it must have been a welcome alternative for Grohl to play so extremely against type in “Studio 666.” It’s the new Foo Fighters horror-comedy movie in which he portrays a demonic version of himself.

“I’ve spent my life trying to be as kind to others as I could possibly be,” says the 53-year-old musician via video link from his mother’s house in Washington, D.C.

“That’s something my mother instilled in me from day one. She’s a public schoolteacher.” (She’s also the author of “From Cradle to Stage: Stories From Mothers Who Rocked and Raised Rock Stars.”) “Be kind to others. But listen, you put those fangs in your mouth and those contacts in your eyes and all of sudden you’re allowed to be a demon? It feels pretty [expletive] good to let it come out.”

Grohl spoke during a round of press interviews for “Studio 666,” the tongue-in-cheek slasher film directed by B.J. McDonnell (he directed “Hatchet III”), that opens in theaters-only on Feb. 25.

The movie tells the cartoonishly bloody tale of the band moving into an Encino mansion to record its all-important 10th album. Then, paranormal things happen that have something to do with grisly goings-on that occurred 25 years earlier during another band’s ill-fated recording session.

Along with Grohl and his bandmates Pat Smear, Taylor Hawkins, Nate Mendel, Chris Shiflett and Rami Jaffee, the movie features guest appearances from Jeff Garlin, Will Forte, Lionel Richie and Whitney Cummings.

In conversation, Grohl is his familiar, gregarious self, his answers dotted with good-natured f-bombs. His beard is flecked with gray and he wears glasses and a T-shirt emblazoned with D.C.’s 202 area code.

Grohl grew up in the District, schooled on punk rock shows at the 9:30 Club. He dropped out of high school at 17 to play drums with hardcore band Scream, which led him to join Kurt Cobain and Krist Novoselic in Nirvana in 1990.

“It’s funny,” he says, lighting a Parliament. “I’m here at the house I grew up in, and I always like to sit down at the dining room table and have a cigarette because” — he slips into a conspiratorial voice — “that’s what I used to do when my Mom wasn’t around.”

“Studio 666” credits “Story by Dave Grohl,” but the movie wasn’t his idea.

In 2019, Grohl rented the 1940s-era house where the movie was filmed to record demos for what would become the Foo Fighters’ actual 10th album, “Medicine at Midnight.” The album, which paired the band with Adele producer Greg Kurstin was released (after a pandemic delay) in February 2021.

When the band was approached about doing a horror movie, Grohl’s first reaction was “That’s the stupidest … idea I’ve ever heard in my life?”

Then, he got to thinking. “I’m like, wait a second. We already have the house. Why don’t we make the record right here, and the take a couple weeks off and then just film some like really low budget run-and-gun slasher film and put it out for the fans?”

Grohl, who cites “The Shining,” “The Amityville Horror” and “Evil Dead” as inspirations, came up with an elevator pitch: “Rock band needs to make record, rock band is sick of using recording studios, rock band finds creepy old house, don’t know the house is …. possessed. They start making a record, singer goes bananas, kills the entire band, goes solo.”

That specific storyline did not hold, once screenwriters Jeff Buhler and Rebecca Hughes got to work. “It snowballed into a full-length feature film … Now, we look at each other and say, ‘Oh my God, we made a movie!’”

Making the movie was a challenge. The Foos finished “Medicine at Midnight,” their most groove-oriented album, in January 2020. The band then got to work on “Studio 666,” but the pandemic shut production down.

There was a seven-month break before shooting was able to resume. “We were one of the first major productions to come back after the first stage of the pandemic. But the hardest thing was keeping this whole thing a secret for two-and-a-half years. And we actually pulled it off.”

For his inspiration to portray demonic Dave Grohl, the singer-guitarist-drummer reached back to previous acting experience.

Back in 2001, Grohl played the devil in a video for the song “Tribute” by Tenacious D, the comedy-rock duo of Jack Black and Kyle Gass. He reprised the role in the 2006 movie “Tenacious D in the Pick of Destiny.”

“They said, we want you to be in the movie, but it’s going to be about six hours of prosthetic makeup and you’re going to be Satan. I was like, Why not? … And I remember the first time I walked on set as Satan, the men looked scared and the women looked turned on. It was pretty … cool.”

Until now, the Foos have not been able to properly tour behind “Medicine at Midnight,” though the group has played sporadic high-profile shows, like a vaccination-required date at Madison Square Garden last June that was the first back at the historic arena, and another one at the Forum in Los Angeles in which he brought out Bushell to play on the 1997 hit “Everlong.”

The band also recently performed a virtual-reality concert directed by Mark Romanek on Facebook’s Oculus platform. The show originally aired after the Super Bowl, though Grohl didn’t know when the game was.

“I know absolutely … nothing about sports,” he says with a laugh. He was “a lacrosse kid” growing up in D.C., “but once I discovered acid and Led Zeppelin, all that went out the window.”

The band plays a festival in Arizona next week and heads to Central America in March before beginning a U.S. tour.

At upcoming shows, the Foos may well play “March of the Insane,” the death metal song that plays a key role in “Studio 666.” And perhaps they’ll throw in a Bee Gees song from their 2021 album of covers of the Brothers Gibb.

But mainly, Grohl says, all he and his bandmates need to know is they’re going to be out on the road playing music again.

“We’ve spent the last quarter of a century hauling our [selves] around to every … nightclub, arena, stadium that would allow us,” Grohl says. “So when it was taken away from us, it stung. Getting back on stage in front of a live audience: That’s what we’re here to do. We’re not here to make horror films. We’re here to be a rock band. When we hit the stage, I’m like, ‘Oh God, I’m so glad this is my … day job.”