It’s the last day of summer and here comes Icona Pop, the inseparable Swedish duo, strolling around backstage in lockstep, waiting for the next hit to show up.

Caroline Hjelt explains it to bandmate Aino Jawo like this: “You’ll be singing something when you’re brushing your teeth, and I’m like, ‘Wait!’ And I repeat it, and you’re like, ‘That’s actually good!’ And we record it on our phone.”

Plenty of Icona Pop songs are born this way. One sings an absent-minded blah-la-la and the other smacks it back like a tennis ball. It only works because Hjelt, 25, and Jawo, 27, are around each other at all times, including right now at Merriweather Post Pavilion on a cloudy Saturday afternoon, where they’re prepping for a rowdy midday performance at Virgin Mobile FreeFest.

If you aren’t familiar with the giddy snarl of Icona Pop’s double-platinum megahit “I Love It,” maybe you’ve heard it sung by Robin Thicke, Cookie Monster or the cast of “Glee.” The song first made rumbles in the summer of 2012, and on Tuesday, the duo will finally release its stateside debut album, “This Is . . . Icona Pop,” 11 tracks of pithy, punchy electro-pop that could transform them from one-hit-wonder-women into Swedish pop royals on par with Robyn, Roxette, Ace of Base and Abba.

“Have you ever seen ‘Pippi Longstocking’?” Hjelt asks. Apparently, Pippi’s cluttered house in the 1969 Swedish kids film is a good place to start when describing Hjelt’s old Stockholm apartment. That’s where the ginger-haired singer met Jawo, at a party, in 2009. The furniture was vintage, the floor was littered with Polaroids and the air was vibrating with Prince songs. The next morning, the two were in a band.

“And we’ve basically been living in the same room, sleeping in the same bed for, like, two years, now,” Hjelt says. “Some days, we don’t even talk. We just hang out.”

Jawo says those silences are never awkward. “That’s when you know you’ve found your soul mate,” she says of their platonic partnership. “When you can actually be quiet a whole day without saying anything.”

The duo’s camaraderie is immortalized throughout “This Is . . . Icona Pop,” especially with “Girlfriend,” a pulsing dance track that braids a vintage 2Pac couplet into a sonic friendship bracelet. But lyrics aside, you can still hear an undeniable intimacy in the duo’s singing, even when it resembles a shouting match.

They first stumbled into their hallmark vocal approach by trying to save time in the studio, singing into one microphone instead of multitracking their vocals. “We thought it sounded so punky and cool,” Jawo says. “But now it’s starting to get hard.”

Hjelt nods. “It’s more like our voices have melded into one,” she says. “Voices have to crack a little for it to sound like two people.”

More than a dozen people offered a hand in the writing and production of “This Is . . . Icona Pop,” including Norwegian superproducers Stargate, Peter Svensson of the Swedish rock band the Cardigans and California producer Nicole “Coco” Morier. But Hjelt and Jawo exude too much personality to get buried by their producers’ cascading electronic melodies or by their own library of influences.

“We did not grow up with just one type of music, but with everything from the grunge, to punk, to hip-hop, to the one-hit wonders. You can really hear that in the songs,” Jawo says “We want people to understand that we’re not just ‘I Love It.’ ”

So if the world hears 10 more hits, great. But ultimately, this is pop music at its most uncynical, the sound of two BFFs emptying out their lungs and their hearts.

“People understand that we’re two best friends doing what we love,” Hjelt says. “It shines through.”