The Weeknd's stardom helped by go-to Canuck songwriter Stephan Moccio

From start to finish — quite literally — The Weeknd's hulking smash album Beauty Behind the Madness features the handiwork of Canadian songwriter Stephan Moccio.

The 42-year-old from St. Catharines, Ont., co-wrote both the album's opener Real Life and its closer Angel, plus its double-platinum centrepiece single Earned It.

If The Weeknd's ascent from melancholy wallflower to perhaps the world's most sizzling pop star seems unlikely, well, so is the odd couple partnership between two Canadians.

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"We don't know exactly how it works," an energetic Moccio said ahead of the Friday release of Beauty Behind the Madness.

"You've got a guy who sings these edgy lyrics and you got a guy who composes classical music and loves pop songwriting, and you put them in the room together, and the result is something really special.

"You wouldn't necessarily think that. I come from the classical world and he comes from the dark hip-hop world.

"But we've become collaborators and friends for life."

Co-wrote Olympics theme & Wrecking Ball

Moccio first met Abel Tesfaye, a.k.a. The Weeknd, when the majestically coiffed singer walked into his Los Angeles studio last October.

Moccio, who co-wrote the 2010 Winter Olympics anthem I Believe with Alan Frew, had moved from Toronto to L.A. back in August 2013. Exactly five days after the father of two uprooted his family to the left coast, Miley Cyrus dropped Wrecking Ball.

Moccio, who co-wrote and played piano on the song, was suddenly in desperate demand.

In the two years that followed, Moccio interacted with no shortage of industry players who were after his apparently gilded touch. But the instant rapport he felt when Tesfaye first walked into his studio was something truly unique.

"We connected very fast — like brothers," Moccio said.

"My chord style at the piano is highly cinematic and Abel was seeking a collaborator like that.... He wanted that 'expensive sound,' as we call it."

With a laugh, he adds: "We're just a modern-day (Burt) Bacharach and Hal David. We need each other. What I spit out will provoke a thought from him, and vice versa."

Tesfaye had to that point become an alt-R&B figurehead, mostly on the strength of his sunless mixtapes populated by dour tours of joyless nights at the club.

Fifty Shades soundtrack success

Though Tesfaye had proven a gift for crafting alluring atmosphere in his music, he had only once penetrated the Top 60 on the U.S. singles chart and had seldom seemed interested in catering to the broadest tastes.

Moccio, however, met Tesfaye at a time when he was reconsidering his pop potential. And coincidentally, Moccio had an opportunity simmering on the back burner that would prove key.

Before meeting Tesfaye, Moccio had co-written with Skylar Grey the haunting piano ballad I Know You, intended to soundtrack the end credits of Fifty Shades of Grey. But the movie's director, Sam Taylor-Johnson, decided she instead wanted a man's voice to coo over the credits, and the studio came back to Moccio.

Of course, he had the perfect candidate. Moccio, Tesfaye and his team began work on Earned It — and wrapped work almost immediately after.

"The song wrote itself," Moccio beams.

The other two songs the pair collaborated on are "classic Stephan Moccio massive productions," he says.

Indeed, Real Life announces itself with a thundershower of strings, while "Angel" is a lurching power ballad with as much carefully orchestrated drama as a reality dating series.

That said, the duo's estimable chemistry isn't necessarily a formula for working quickly.

"I'm also the first to say that Abel, like myself, as brilliant as he is, can be his own worst enemy," Moccio said. "Because he's constantly striving for perfection.

"The song could be considered done and he may come back and tell me his vocal is just not good enough on bar 52, beat three. And I may do the same on bar 60, obsessing over the fact that I played the wrong bass inversion."

The month after Tesfaye met Moccio, the singer landed his first Top 10 hit with the Ariana Grande collaboration Love Me Harder.

Performed together on Tonight Show

In less than a year, he's scored three more Top 10 hits, including his first No. 1 in Can't Feel My Face. It's a near-unprecedented run for an R&B singer, particularly a press-averse Canadian who sings ennui-haunted odes to cursed drug trips.

Moccio, for his part, isn't surprised at all.

"I knew it the moment he walked into my studio — 10,000 per cent," he said.

"I saw fire in his eyes and commitment and discipline that he really wanted it and he knew what it took to get there."

Whenever possible, Tesfaye has brought Moccio along for the ride.

They performed together on Jimmy Fallon's Tonight Show recently — Tesfaye snapping his fingers along to Moccio's pounding piano chords — and at several Grammy-week gigs. Moccio had to turn down Tesfaye's invitation to join his headlining Coachella set because he was still working on the new album.

Onstage or not, Moccio plans to be at Tesfaye's side well into the future.

"The marriage is in a lot of ways a really perfect one on a creative level," Moccio said. "We both know it. His team knows it.

"We're already thinking of the next album."