For the songwriter, the most amazing thing about Wiz Khalifa's "See You Again" being the top-watched YouTube clip is that he got to be in it at all.

When Wiz Khalifa's "See You Again" music video featuring Charlie Puth dethroned PSY's "Gangham Style" as YouTube's most-watched video with nearly 3 billion views on Monday, it did so without having been a viral phenomenon, riding instead on emotional power and the influence of the Fast and Furious film franchise. But for Puth, who co-wrote the Furious 7-closing ballad with DJ Frank E and Khalifa, what's most amazing of all is that he was even featured in the video in the first place.

"I don't know if a lot of people know this, I wasn't supposed to be in the video," Puth tells Billboard. "I wasn't supposed to be on the song; I was only supposed to be a writer on the song. I was a brand new artist, I wasn't cool enough to be part of the franchise yet, I wasn't big enough, but I proved everybody who was close-minded wrong. Everyone on my record label stuck beside me and my management.

"I'll never forget I ended up calling them from around this big conference table on the phone, and they were explaining the reasons why it was going to be sung by this artist and blah, blah blah, I'm not going to name any names, but... I said, 'That's great. Your movie comes out in a week and I'm not gonna give you the song.' And I hung up the phone and when I said that miraculously I was in the music video."

Though Puth would not state to Billboard what artist Universal Pictures had originally wanted to sing "See You Again," earlier this year he told People his vocals on the hook had originally been recorded as a reference possibly for Sam Smith. Mike Knobloch, president of film music and publishing at Universal Pictures, denies Smith was ever discussed for the track.

"I don't hold any grudges," Puth says. "I'm actually really good friends with everybody who didn't necessarily believe in me at first, I've worked on projects with them since then and everything is all good now but, you know, I had to prove myself."

Knobloch confirmed with Billboard that other performers were discussed to sing on "See You Again," but insists that exploring various options was standard business procedure and not personal. He explained that the studio's relationship with Puth began as a songwriter, with whom they worked closely to craft the song to excellently soundtrack the film's emotional sendoff to the late Paul Walker's character, but it wasn't until much later that he entered conversations about performing on the track. With that, came the at times "uncomfortable" debate about whether Puth -- a then unknown 23-year-old artist -- was the best fit for the Fast and Furious franchise, especially to be tasked with something as sensitive as honoring its star actor in this way.

Ultimately, Knobloch says, they decided the song didn't sound right without Puth's voice.

"It was important to get it right and to make sure from all angles that it went out in the most high integrity way possible, which in hindsight that's exactly what we did," he says. "And after that exploration, we can look back and say that it went exactly the way that it should have. "

By strong-arming his way onto the song, Puth helped launch his career in a big way, as it was only his second single released on a major label and went on to top the Hot 100 chart for 12 weeks.

Puth's career began as a teenage YouTube musician from New Jersey, posting comedy videos and acoustic covers. A couple years on he was signed to Ellen DeGeneres' eleveneleven label after the talk show host saw his cover video of Adele's "Someone like You," but "See You Again" is what helped elevate him to a mainstream level. Puth tells Billboard that writing the song led to his label deal with Atlantic Records and publishing deal with Artist Publishing Group.

"I wrote the song independently and then got to negotiate anything I wanted," he says with a laugh. "But I didn't cash out, honestly. I respectable offers and I'm glad I did it that way instead of saying, 'Give me $5 million right up front....' The song had a lot of success, so I took advances as if had written a C+ song."

As for actually writing the Grammy-nominated song, as Puth has said in past interviews, it took him just 10 minutes.

"Your brain is an amazing thing when you allow it to relax on a July day in 2014," he says. "I think I was just in a good mood."

Puth wrote the song during a session with DJ Frank E that was set up by Atlantic during a sort of try-out week where the label flew Puth to Los Angeles to see if they wanted to sign him. He recalls being checked into a "crappy" hotel ("Because why would they put me in a nice hotel, who am I?" he says) but he was "way too bougie for that." So he took his "YouTube money" and booked himself a week at the 5-star Montage in Beverly Hills.

"I had never been to Beverly Hills before and I was so enamored by Hollywood and all of its luxurious things and all of the Lamborghinis everywhere and I was in such a different world, I was Uber Black Car-ing everywhere, my mind jumpstarted and I felt like a famous songwriter," he says. "I felt like Diane Warren and David Foster and I pulled up to the studio in my Uber Black Car that I pretended I had all day and I was like, I'm it! I kind of had to trick my mind into being really confident."

Conjuring the loss of one of his own friends in a car accident two years prior, after 10 minutes it all amounted to Puth's breakout hit. Needless to say, he no longer has trouble conjuring confidence.

"'See You Again' being such a universal song has allowed me to figure out my musical self. It hasn't corned me into, 'Oh, he has to be jazz piano player who does pop music,' or, 'He has to be a ballad guy.' It's allowed me to take many shapes and forms in my music," he says. "It's just amazing how 'See You Again' has allowed me to spread my musical influences all over the place."