In December 2012, something shifted markedly in the musical mind of Tegan Quin, one half of the critically acclaimed Canadian indie-pop duo.

It happened, she says, partway through a performance on The Late Show with David Letterman and was what she describes as a “Holy shit! We can’t turn back now!” kind of moment.

The revelation comes partway through a conversation about the duo’s recently released seventh studio album, Heartthrob, a buoyant pop record that is, by Tegan’s own laughing admission, “our completely shameless attempt to make a mainstream pop record that still has substance and meaning.”

Best-known for finely crafted, occasionally pop-inflected, indie folk-rock music, the new album is a huge departure for the 32-year-old twin sisters and one that she admits took “quite a lot of courage” to write, record and, now, put out into the world.

Its conception and creation was a process that began following the release of their previous album, 2009’s Sainthood and later cemented by unexpectedly successful collaborations with artists like superstar DJs Tiesto and David Guetta, both of whom were making music completely different to the sort traditionally associated with Tegan and Sara’s oeuvre.

“We’ve used collaborative work as our way to expose ourselves to new people, I think, and a lot of the fans that have come to us since then have come from that dance/pop sort of world. But, yeah, it dates back as far as coming off tour for Sainthood, really, and then those collaborations,” Tegan reveals.

“But, you know, weirdly, even though the album was all done, all ready to be released, it was when we were onstage, singing the record’s first single, ‘Closer,’ which had had about 400,000 streams since we put in online and I just thought: ‘Well, it’s too late now. We wanted to make a song I could imagine playing in a stadium, and there I was, performing it on Letterman!”

For the duo, Tegan says that the fear of transitioning from the sound for which they were known, and with which they’d not only made their name but also amassed a large, fiercely loyal international fan base, came not only from worries about alienating those fans, but also failing in the endeavour.

“There was definitely fear. We didn’t know if we could do it. But Sara and I have been writing together for, like, 15 years and we can’t tread water. I don’t want to be making the same record-over-and-over again. We have fans that love [2007 album] The Con and ask for another album like it, but I’m always like: “No!” Because we know that if we did put out another record that was like it they’d be saying, “What are you doing? Trying to sell us the same old shit?’ Plus, who wants to do that, anyway?” she laughs.

For the openly gay siblings, who have always used their public profiles to support GLBT rights and gay marriage across North America, one of the driving forces behind their music is connection and transformation – they make music because they’re driven to, yes, but also because it’s their way of connecting with their fans and, hopefully, contributing to change in the world around them.

“That is pretty much what drives Tegan and Sara. People have used words like ‘selling out’ when talking about Heartthrob and I just wonder what that even means? I have tried not to think for more than a second about any of this stuff people have said about capitalising on our existing fan base and betraying their expectations by making Heartthrob the sort of record it is because it’s simply not true,” Tegan admits.

“There was definitely hesitation before we began and we were like: ‘Is this where we want to go? Do we want to go down a more commercial path? Or do we want to stay more obscure and not even mess with the mainstream?’”

It is a conflict that, she says, quickly resolved itself once they started writing and knew they had the material to make the album they aspired to create. They even broke their previous taboo on writing together and collaborated, something Tegan says is “pretty astonishing in and of itself.”

“We never wrote together before. It never worked. But we were inspired by the way we’d collaborated when we were working with Tieto and David, which was basically writing stuff and sending it back-and-forth between ourselves, and decided to give it a go. I mean, a bridge, for example, is supposed to feel like a left-turn in a song, it’s supposed to make you feel like you’re being taken into a complete different song almost and I have just never been the best at that,” she elaborates.

“Now Sara, on the other hand, is great at doing that, so I used her to help me write all my bridges, because I knew I wanted the songs to go to a completely different place, and Sara was able to jump in and do that, so it was actually great. It was a really great learning experience and I think it made the record stronger and I think, for our fans, it’s something new, too, because we sing pretty much all of the record together, and that’s pretty much the first time we’ve ever done that.”

In the end, the twins found themselves with a pool of songs that dealt, both directly and indirectly, with love and relationships that were both successful and unsuccessful, happy, sad and everything in between.

They knew they wanted to work with multiple producers but had no preconceived notions as to who those producers would be or the neo-80s nostalgia pop feel that would eventually permeate the sound of the album.

They were aware of the electro-pop vein in which they were headed, but ultimately unsure exactly what form it would take once they were in the studio and working with producers.

“In terms of that, the first producer I met with was Greg Kurstin and I just loved him. The people he’s worked with, like Pink … it was like he was working with Barack Obama in my mind, you know? I knew that, even if he couldn’t do our whole record, I really loved the way he worked, thought he was really cool and that, hopefully, he’d work with us on a few songs at least,” Tegan says.

In the end, Kurstin produced eight of the tracks on Heartthrob and the remaining four were produced by Mike Elizondo, famed for his work with the phenomenal New York songstress Regina Spektor, and Justin Meldal-Johnson, the preferred producer of Beck, M83 and Nine Inch Nails.

The songs themselves were written out of a mix of personal experience and observing and reconceptualising the stories and experiences of those around them, something Tegan says “was necessary, given that things change, emotionally, and that’s not always what you need for songwriting.”

Tegan and Sara return to Australia for an extensive tour in April and May, something she’s clearly very excited about. In addition to headlining the Groovin’ The Moo festivals in several states, they’ll perform sideshows, one of which brings them back to Brisbane, a town she speaks of with fondness.

“We love Australia so much that, sometimes, really I feel like we love Australia more than Australians love Australia! I really love Brisbane. You’re good people there and the audiences are always really loving and supportive,” Tegan enthuses.

“When you make an album and release it, such a big part is touring. You spend months and months and months on the road. We try and get down to see you guys once or twice an album cycle … and it’s like a second home. We always really, really look forward to coming there and giving you our best!”

Heartthrob is out now through Warner Music Australia.

Tegan and Sara play at the Tivoli on Tuesday, 30 April and tickets are available from the venue or Ticketek: http:/www.ticketek.com.au

– Heidi Maier.