How The Chainsmokers went from novelty act to chart dominance

Bands meet in the strangest ways.

Sonny Bono talent-spotted Cher in a coffee shop. Kiss hired their drummer after he placed an ad in Rolling Stone magazine saying he was "willing to do anything". REM's Mike Mills and Bill Berry were sworn enemies until a mutual friend asked them, separately, to a rehearsal.

Berry wanted to storm off... but his drums were too heavy to allow a dramatic exit, so he stuck around and the history of rock was changed forever.

The Chainsmokers, it is fair to say, do not have such an interesting story.

"Our manager's intern introduced us," says Alexander Pall.

"We talked about our passion and interest in dance music and we took a shot."

Despite those undramatic beginnings, the duo, in which Pall is joined by Andrew "Drew" Taggart, have created one of 2016's biggest hits.

Closer, external is a duet between Taggart and alt-pop heroine Halsey, who portray a couple rekindling their romance after a four-year break, only to remember all the reasons it didn't work out in the first place.

"We wanted to write an unsexy sex song," says Taggart. "And every line in Closer is pulled from, like, five of my past relationships."

The lyrics are sentimental but quirky. "Baby pull me closer in the backseat of your Rover, that I know you can't afford," sings Taggart, before the encounter continues on a "mattress that you stole from your roommate back in Boulder".

It's unusual to hear such autobiographical, observational phrases in a dance track - but that's exactly why Closer broke free of genre constraints, topping the UK charts for four weeks and, at one point, racking up more than five million plays on Spotify every day.

"It's hard to comprehend, to be honest," says Pall.

"We wrote it and recorded in our tour bus and we didn't immediately say, 'Wow, this is really something,'" adds Taggart.

"We didn't even know it was going to be a big-selling song."

There was one small snag along the way. A couple of weeks before Closer came out, it emerged that its riff bore similarities to a piano line on The Fray's 2005 single Over My Head (Cable Car), external.

"Luckily, someone in Sony Australia was like, 'Hey, by the way, did you guys notice this?'" says Pall. "We just went, 'Oh my God!'"

The Fray were hastily given writing credits on the song, allowing them a share of all future royalties.

"I'm really happy we took care of it the way we did," says Pall. "It would have sucked if it became a headline, simply because of a lapse of thought or whatever. That takes away from the song."

"We're lucky it was resolved that way and not like Blurred Lines," adds Taggart, referring to the controversial trial which found Robin Thicke and Pharrell Williams guilty of copying Marvin Gaye's single Got To Give It Up.

"That case sets an insane precedent for what is plagiarism and what is inspiration. Pharrell said in an interview that he used to listen to Marvin Gaye and that was used against him. He listened to Marvin Gaye? Yeah, so has everybody that exists on the planet."

Growing up in separate states of the US, music was the unifying feature of The Chainsmokers' formative years.

Taggart was born and raised in Freeport, a coastal town in Maine with a population of 7,700.

He was a studious teenager, who found time to set up an investment club for his classmates. "I thought it was crazy that kids weren't taught about taxes and what to do with their money before they leave High School," he says, cringing at his "dorky" hobby.

Pall was more rebellious. The son of a New York art dealer, who hung Picassos in the family's Manhattan home, he says he spent his school years smoking marijuana and throwing parties.

When Napster emerged as a source of free music in the early 2000s, it was a revelation. "I destroyed my family's computer," he laughs. "So many viruses." But it gave him a musical education that inspired The Chainsmokers' mix of indie and dance.

Indeed, the duo's introduction to dance music came late - in Taggart's case, on a school trip to Argentina. Previously, they were into punk and emo bands like Dashboard Confessional and Death Cab For Cutie.

As they refined The Chainsmokers' sound, those were the groups they turned to for a lyrical blueprint.

"When we started, there was so much European dance music. A lot of these artists were Dutch and Swedish and it's different to sing in a second language," says Taggart.

"We'd look back to those bands we loved and think, 'Why isn't this making its way back into our music?' And when we applied that lyrical process, that's when we realised that what we were doing was interesting."

But it took a while to get there. The band's breakthrough single #Selfie, external was a big, dumb party anthem built around the inane ramblings of a drunk girl. The key lyric: "But first, let me take a selfie".

"It was a novelty hit and I'm sure a lot of people doubted we'd be back," admits Taggart. "But the only thing you can do after your first hit song is keep trying to write another one."

"It taught us a lot about us and the music business," adds Pall. "And, you know, obviously, if I could make it not be a song about selfies, that'd be great - but that's just the way it is and we're all good where we are now."

And right now, they are one of the most in-demand groups on the planet, with Bono and Chris Martin among the names in their phonebook.

"A year ago we were not getting as many of these calls. Now we're working with a lot of artists who we're huge fans of," says Pall.

The limelight hasn't always flattered the band, however. A profile in Billboard magazine, external painted them as beer-swilling misogynists, while Pall made headlines after telling a reporter that Lady Gaga's comeback single, Perfect Illusion, "sucks".

"Who cares what I think?" he asks, still bewildered by the backlash. "No-one's cared whether I thought something was good or bad for 30 years.

"I do feel badly about it, because it was never my intention to be disrespectful. Lady Gaga is an amazing artist - and she hit us back with the perfect response". (Gaga tweeted the band a link to her follow-up single, A-Yo, saying: "Maybe you'll like this one better, external").

The musician says he's still "in an adjustment phase", as he grapples with the idea that people are paying attention to what he says.

"It's a lesson learned."

Perhaps that's why The Chainsmokers are so cagey about their future plans. After a run of hit singles - Don't Let Me Down, Roses, Closer and All We Know - most bands would be prepping an album. But Pall side-steps the idea in almost every interview.

"We don't want to put out an album that's a collection of singles. We want to have a concise message throughout our discography and we're waiting to figure out exactly what that message is going to be."

They "definitely have the songs" to make a full-length record, he adds, but given that their biggest audience is on streaming services - where fans favour tracks over albums - maybe there's no point.

"To us, it's just about putting music out consistently. We don't want to put all this work into making an album of 12 songs and some of it gets overlooked".

Instead, the band are biding their time by releasing an EP, Collage, which will combine all of their 2016 singles with a brand new song, Setting Fires.

"The idea is that we got a lot of new fans with Closer and, by creating an EP, it will hopefully introduce them to our older work."

"It's really exciting," adds Taggart, "but it's taken a lot of steps to get to this point. It's not like we suddenly woke up one morning and felt, 'Wow, it's arrived', but we're really pumped - and there are still big things to come."

If he's right, and the band steer clear of controversy, they could become one of dance music's few genuine crossover acts.

Either way, one thing's for certain - that intern has a bright future in the music business.

The Chainsmokers' new EP, Collage, is out today.

Follow us on Twitter @BBCNewsEnts, external, on Instagram at bbcnewsents, external, or if you have a story suggestion email [email protected], external.