Back in 1993, Depeche Mode singer Dave Gahan suffered a minor heart attack onstage during a show in New Orleans — brought on by an exhausting touring schedule and heavy drug and alcohol use.

But just a month ago, Gahan’s heart skipped a beat for an entirely different reason.

As the Brit band (who have sold more than 100 million albums during the past 37 years) was beginning to promote its new album, “Spirit,” white supremacist — and self-professed Mode mega-fan — Richard Spencer said that the electro-pioneers were the “official band of the alt-right,” in an interview at the Conservative Political Action Conference in Washington, DC, before being kicked out by CPAC organizers.

“My phone kept ringing and ringing,” Gahan, 54, tells The Post, still incredulous at the thought. “I had to tell everyone, ‘No, we’re not the official band of the alt-right.’ ” He’s recounting the story during an interview at the Avatar Studios in Hell’s Kitchen (formerly the Power Station) — where Madonna recorded “Like a Virgin,” and artists such as Springsteen and The Rolling Stones also made classic albums.

“I could understand some commie jumping on us because of our history and working-class background,” Gahan says. “But this was ridiculous.”

The band said as much in a polite but firmly worded statement distancing themselves from Spencer and his extremist politics. In person, Gahan is far less courteous.

“He’s a dangerous person — he’s well-educated and he’s using it to promote hate and fear. I saw the video of him getting punched [during protests at the inauguration of President Trump]; he deserved it.”

‘I could understand some commie jumping on us because of our history and working-class background. But this was ridiculous.’ - Dave Gahan

As surreal as that particular episode was, it’s strangely fitting that it would happen in the run-up to the release of Depeche Mode’s most politically and socially conscious album in years. Lead single “Where’s the Revolution” sets the tone. But Gahan says “Spirit” (out March 17), the band’s 14th album, is less about insurrection than it is about information.

“Fundamentally, this album is about being informed,” he explains. “Even my son Jimmy will say to me, ‘Be careful what you read in the New York Times. Make sure you read other stuff to balance it out.’ He bought me a subscription to the Atlantic so I could read the same story, but from a slightly different perspective.”

Compared to the brooding, stripped-down 2013 collection “Delta Machine,” “Spirit” sees the band returning to a more classic Depeche Mode sound that helped the group (completed by keyboardist/guitarist Martin Gore and keyboardist/bassist Andy Fletcher) build up a cult fan base during the ’80s.

After forming in Basildon, England, and releasing their debut “Speak & Spell” in 1981, the band won gradual critical acclaim with albums such as “Black Celebration” (1986) and “Music for the Masses” (1987). By 1990, singles such as “Enjoy the Silence,” “Personal Jesus” and “Policy of Truth” (from “Violator”) sent them into the mainstream.

Although it’s been years since they’ve had Billboard Hot 100 hits on that scale, their fans still fill up arenas all over the world as a matter of course, and New York City is no exception. The band will play two nights at Madison Square Garden in September — 30 years after they first played the venue.

This year also marks a personal anniversary for Gahan. The frontman moved to New York City in 1997 and cleaned up, following a period living Los Angeles that coincided with the absolute nadir of his drug addiction. His heart famously stopped for two minutes in 1996 following an overdose of cocaine and heroin. Gahan’s life was saved by paramedics, who thankfully revived him.

Gahan and his wife, Jennifer, have a 17-year-old daughter, Stella Rose. Their son, Jimmy, is in his 20s. Gahan also has a son, Jack, 29, from an earlier marriage.

These days, Gahan’s exercise regimen has left the singer looking like a picture of health. At a recent interview, he’s slim, dressed in black, boasts salt-and-pepper hair (mainly pepper), and allows himself a tasteful amount of gold jewelry on his fingers and wrists.

Although Gahan still speaks with a broad southern English accent, you can hear the experience of 20 years in Gotham inform his opinions and conversation. He talks about gentrification, real estate prices and the changing face of downtown Manhattan with all the brio and savvy of a chatty yellow-cab driver.

He’s even a long-suffering New York Knicks season-ticket holder, explaining that he goes to most games with Jimmy. “He was always been into basketball, and it was a great thing to do as a bonding exercise,” Gahan says. “They’re not doing that well, I admit. Melo [Carmelo Anthony] puts up the points, but it’s better when he notices the rest of the team and pulls them in! My favorite player is probably [Kristaps] Porzingis. He’s already great, but I think he’s gonna develop into something really special.”

Over the years, living in New York City also brought Gahan a little closer to one of his musical heroes, David Bowie. Gahan and Bowie first met in 2002, when Bowie played his classic album “Low” at an invitation-only show at Roseland Ballroom. The two developed a friendly relationship as their daughters both went to the Little Red School House in the Village.

“I’d see David at the school Christmas concert and things like that,” he says. “You’d see him with his flat cap on! Then he disappeared for about a year, and the next time I did see him at another school thing, he looked different. I said to my wife, ‘He doesn’t look well.’ That was a couple of years before he died.”

For Gahan, it was much more than just a celebrity sighting. Not only was Bowie a central inspiration for all members of the group, he was also the reason Gahan ended up as singer. In 1980, Gore, Fletcher and Depeche Mode founding member Vince Clarke were in a group called Composition of Sound, but were struggling for a real frontman. They happened to hear Gahan singing Bowie’s “Heroes” in an adjacent rehearsal room, and invited him to join. “It wasn’t just me singing, it was a few people singing, but I said it was me,” Gahan says with a laugh. “That’s how I blagged [faked] my way into Depeche Mode.”

On the morning of Jan. 10, 2016, Gahan’s wife, Jennifer, told him about Bowie’s death and he immediately broke down. “I hadn’t cried like that in a long time,” he says. “I regret not talking more to him and telling him how much his music brought me through my whole life. Without punk music and people like him, I probably would have ended up being a petty thief, stealing lead off roofs!”