It was the Tweet that shook Carly Rae Jepsen’s world.

When teen superstar and social media phenomenon Justin Bieber first heard the Mission, B.C., native’s catchy dance-pop number “Call Me Maybe” last year and tweeted an endorsement to his 15 million (at the time) followers, Jepsen’s life changed forever.

“It ended up really igniting right away: I was No. 11 on iTunes at the time, and he tweeted and we were No. 1 within the day,” remembers Jepsen, a 2007 finalist on Canadian Idol. “Not only in Canada, but in countries I had never visited, like Germany and Australia and New Zealand – they were kind of getting wind of it, and I was getting Twitter followers by the thousands. I was amazed what one little tweet could do.”

It didn’t stop there. A small cadre of Bieber’s pals – his girlfriend Selena Gomez, actress Ashley Tisdale and members of the band Big Time Rush – joined him to film a video of the song that exploded virally. This set off a new trend of celebrity versions and adaptations – ranging from Katy Perry and Sesame Street‘s Cookie Monster to former U.S. Secretary of State Colin Powell – providing their own renditions of “Call Me Maybe.”

“I was getting Twitter followers by the thousands. I was amazed what one little tweet could do.”- Carly Rae Jepsen

But it was immediately after the Bieber and friends video – clocking in at more than 45 million views as of press time – that Jepsen received the call that would turn her life cyclonic: an invitation to join the Stratford, Ont., native and his manager Scooter Braun’s new label, School Boy Records, distributed worldwide by Interscope. (Jepsen remains on 604 Records in Canada.)

“Scooter said, ‘Justin really wants to do this. I really want to do this. Come to L.A. and let’s begin.’ My tour wrapped up and I flew down there.  Two nights before I left, I went on Facebook and saw the viral video and went, ‘Holy shit, this is crazy!’”

Since then, Jepsen has been criss-crossing the planet, appearing in Australia and the U.K., where the song has topped the charts.  She also spent five consecutive weeks at the peak of the Billboard Hot 100, and by the time you read this, sales will have probably passed the six million mark in North America alone.

And she’s been busily creating the full-length follow up to her Curiosity EP (released earlier this year), writing and recording with a cast of characters that includes LMFAO’s Redfoo, OneRepublic’s Ryan Tedder, Owl City and the fellow Canadians with which she’s built a creative core: her longtime guitarist Tavish Crowe, Marianas Trench singer-songwriter and frontman Josh Ramsay, and producer Ryan Stewart. To further complicate her life, she’s working on the album while doing TV promotional appearances for the single, appearing on numerous TV award shows, touring incessantly and opening for Bieber on his Believe tour, including a free show in Mexico City that reportedly drew 300,000 fans. “It has been a whirlwind, but a very enjoyable one,” Jepsen reports after an early morning arrival in L.A., following a gig in Ohio.

So how did she come to write her flirty anthem of instant attraction that has taken the world by storm?

“The first line of the song, the phrase line, ‘Before you came into my life, I missed you so bad,’ was something I was just humming to myself while I was hanging out at my uncle’s house in Mission,” Jepsen explains. “It was written for a guy I’m seeing today, my boyfriend – the idea that I knew that something was missing and it was him.”

Jepsen further fleshed out the idea with Crowe. “It was kind of an acoustic song that my Tavish and I were jamming on when we were on the road together,” says Jepsen.

Jepsen had already met Ramsay while opening shows for a Marianas Trench tour, and recruited him for vocals on “Sour Candy,” a track from her 2008 Tug Of War album. “When I showed up at Josh’s for my second writing session ever, he asked me to play any ideas that I had. I played him the beginning of ‘Call Me Maybe,’ and, at that time, the chorus was a pre-chorus. Tavish and me had a whole different chorus in there, and when Josh heard it, he said, ‘No, let’s cut that out and let’s repeat that pre-chorus because that’s definitely the hook.’

“Josh has an amazing sensibility of knowing how to ‘pop-ify’ a song. He’s very genius when it comes to that kind of stuff. Tavish and I didn’t think twice – we just listened to him and followed his lead. The lyric, the rest of the song, we ended up stripping away the verse that was there, and Josh and I re-worked that.”

Jepsen evolved the song further with Ramsay over a few days, increasingly excited by its potential. “I remember I was pretty excited because I came in the second day and had new verse lyrics, too,” she recalls. “I liked the idea of it being a little ‘fantasy-ish’ for a pop song. I sang it to Josh and he was stoked about it.

“Every day another one of us would bring in another idea, and the cool thing was, no one ever said, ‘No, I don’t like that.’ It was always fully embraced.”

One more important piece of the puzzle remained, and that was the mix from Dave “Rave” Ogilvie, the veteran producer and remixer who’s worked with Nine Inch Nails, Tool, David Bowie, Skinny Puppy and others, and who gave “Call Me Maybe” its edgier dance-pop sound.

“Every step of the way was crucial,” says Jepsen. “Josh’s involvement changed the song completely. Dave Ogilvie’s involvement changed the song completely. It was just kind of cool to see the different stages and colours of it.” The whole process took approximately five days. “It was kind of easy,” she says.

“Call Me Maybe” was just one of approximately 55 songs Jepsen had written while prepping initially for an album to be produced by Stewart. But even she was surprised at the dance-pop turn her music took, revealing that she was expected to create a different kind of album altogether.

“I just remember going into the studio with Ryan Stewart and with every determination that I was going to do this folk-ish record, because that’s what I had been signed to 604 to do,” recalls Jepsen, who’d been listening to albums by Robyn and La Roux at the time. “But I would go in there and I always be inclined to ‘dance-ify’ it, and these melodies were happening that weren’t totally folk.

“And Ryan – God love him, he’s been with me from day one of this adventure – was kind of doing the same thing, so we just went where we were feeling attracted, and that was definitely towards more of a pop world.”

Jepsen’s sudden success may be a surprise to the mainstream world, but ex-Canadian Idol judge Zack Werner always felt she’d be “massive.”

“The things that were very clear about her from the beginning were that she had this little-girly quality that was incredibly appealing right off the bat, and you knew that as soon as she was on the radio that people would recognize her,” says Werner. “Coming up with the right songs is another story, but certainly the charisma and tonality was there, and the coquettish cuteness of it was there immediately.”

Werner also praises her upbeat attitude: “She was always positive, always humble, really grateful and really open from the beginning, so I’m not surprised she had the right attitude and the right sense of self to work with people in the right way to succeed.”

Even as she rides her ever-expanding waves of popularity, Jepsen continues to write as prolifically as she did before her career took off. “I didn’t know if I was going to seize up in this, or go through one of these writing sprees that sometimes can happen, and it’s very definitely the latter,” she says. “I’ve gone through this writing spree that really hasn’t let up.”

Although the next few years of her life will be occupied supporting the upcoming album, Jepsen continues to think long-term as she reaches the stars.

“As much as I’m enjoying this ride, and I don’t want to get off anytime soon, my goal has always been five years from now to get to enjoy the luxuries of having a toned-back life with a family, and kids, maybe,” she reveals.

“Maybe I’ll just write for other people or be involved in lyrics. It doesn’t hurt to have a library of unused material just in case, you know?”