"I’d be lying to say that I knew the song was going to be a career-changer for me,” the pop star says of her biggest hit.

"It’s interesting, the songs that people connect to,” Carly Rae Jepsen tells Billboard. "That song, for me, has always been a little bit about how you wish you would have the confidence to act in real life. It’s the more fantastical side of things, where you go up to a complete stranger and do something wild that makes you feel alive. I think that everyone has a secret part of themselves that wants to have the confidence to do that.”

Jepsen, of course, is talking about “Call Me Maybe,” the song that turned her from a singer-songwriter who finished in third on Canadian Idol to an international pop star. Initially released in 2011, the song slowly became a hit in Canada, then got noticed by pop superstar (and fellow North-of-the-Border artist) Justin Bieber; from there, “Call Me Maybe” morphed into a YouTube phenomenon and radio giant, spending nine weeks atop the Billboard Hot 100 chart and becoming the song of the summer in 2012.

And a lot of that whirlwind success is thanks to a chorus -- “Hey, I just met you / And this is crazy / But here’s my number / So call me maybe” -- that remains amazingly simple and impossibly buoyant. It is, without question, the greatest chorus of the 21st century so far — although it almost wasn’t a chorus at all.

"I was in Vancouver at my apartment, with [co-writer] Tavish Crowe to begin with, and he was just strumming some chords, and I sang out what I thought was a pre[-chorus],” Jepsen recalls. “We had a verse, we had a completely different chorus, and I thought that what I was singing at the time -- ‘Hey, I just met you, and this is crazy’ -- was just, like, filler lyrics. I mentioned to Tavish that we would fix them later, and he said, ‘No, I think they’re kind of quirky and light-hearted and fun. I think we should keep those.’”

The next day, Jepsen and Crowe brought the song to Josh Ramsay, the leader of pop-rock group Marianas Trench, who suggested that they turn the song’s pre-chorus into its proper chorus. “He went, ‘That pre-chorus is way hookier than the chorus that you guys have, so let’s repeat it,’” says Jepsen. From there, “Call Me Maybe” -- originally more of a folk-leaning track, in the vein of Jepsen’s earlier singer-songwriter work -- was re-imagined as a bubblegum pop track by Ramsay, who ended up producing the song. “He got inspired and started adding strings," remembers Jepsen. "before we knew it, it had this whole new life.”

Jepsen does not have one songwriting process that she abides by -- she cannot say if “Call Me Maybe” took her longer than any of her other songs to write -- but she says that the common thread of her music-making is trying to find a feeling of unadulterated joy, scribbling that down, and then returning to that moment and analyzing it whenever the euphoria wears off. When she and Crowe first wrote the passage that became the “Call Me Maybe” chorus in her living room, Jepsen recalls “feeling almost childish, youthful, and trying to find the melodies that match that feeling.” But even when the song was finished, she still wasn’t sure it was going to be a single, let alone her defining radio hit.

"I’d be lying to say that I knew the song was going to be a career-changer for me,” she says, "but I did notice this reaction when I played the song for other people, as one of the two contending songs for a single at the time on my Canadian label [604 Records]. There was another song, ‘Curiosity,' and there was this one. I would have family vote and friends vote, and everyone would just come back to something - they would call me and say, ‘There’s something about that “Call Me Maybe” song. I really think you should go with that one!’”

Following the single’s release in September 2011, Bieber heard the song on Canadian radio, and a few months before releasing his Believe album in June 2012, he and his pals (including then-girfriend Selena Gomez) made a YouTube video lip-synching to “Call Me Maybe.” The song quickly rose on the Hot 100 in the U.S., and Jepsen spent the back half of 2012 as the opener on Bieber’s Believe tour, and as the newest signee by Bieber’s manager, Scooter Braun.

Before long, “Call Me Maybe” had become not just a smash single, but a pop culture touchstone. Jepsen watched everyone from Katy Perry to Cookie Monster offer riffs on her first radio hit, from every morning show to every late-night television host, and feel floored (and a bit unprepared) for that kind of attention.

"Fame and celebrity has always been a slightly uncomfortable thing for me, so if you’ve seen throughout the years, I’ve changed up my look a lot,” says Jepsen. “Right after I had gone from brunette to redhead [in 2013], I was at the airport, and this little girl who didn’t seem too sure whether or not I was me tried to test out the waters. She didn't approach me, but was just standing right next to me in the magazine line of the store, and singing [‘Call Me Maybe’], from start to finish, just to see how I would react. I felt like I couldn’t leave, either -- it felt like a performance. It would have been rude to walk away, so I just kind of hung out, and she slowly walked away. I was like, ‘Cool.’”

In the nearly five years since “Call Me Maybe” hit No. 1, Jepsen has remade herself as a folk hero of ‘80s-inspired pop music; her 2015 album, Emotion, is one of the most exuberant (and best-reviewed) pop albums of the decade, and the 31-year-old has collaborated with indie-leaning artists like Blood Orange and Bleachers after working with Bieber and Owl City on her “Call Me Maybe” host album, 2012’s Kiss. Having been able to successfully move on to a new sound while scoring a few more hit singles ("Good Time" with Owl City, "I Really Like You") but not feeling the pressure to replicate the enormity of “Call Me Maybe,” Jepsen says she can look back at her breakthrough hit with a new appreciation. "I haven’t talked about it in a while, and I realized that my ‘Call Me Maybe’ hangover’s over!” she says with a laugh.

So in 2017 — as Billboard declares its chorus the best of the century — what does “Call Me Maybe” mean to Carly Rae Jepsen? "I think it’s been a different relationship that I’ve had with it all along the way,” she says. "At the beginning, it was a total roller coaster, like, ‘What’s going to happen next?' And after that, there’s this terrifying feeling of, 'Oh god, what if it’s the only music that I create? What if it defines the genre of what I do from now on, and what if I grow into wanting to do something different?' That inevitably did happen. It’s nice now to talk about it, because I feel like whatever was built up around that song was quite let go of. And I can enjoy playing it in [my live] set and feel like it’s this sort of nostalgic celebration, and still get to enjoy the other songs off of Emotion and be excited for what I get to create in the future.

"It’s a gift to have a song like that,” she continues, "because it’s allowed me now to start to be able to make, without sacrifice or compromise, the exact music that I’ve always dreamed of making. ‘Call Me Maybe’ was definitely a part of my story and part of how I look at myself as an artist, but that’s always evolving. It’s nice to have the confidence and freedom to be able to change like that."

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