Ariana Grande had no idea that when she hit the studio to record "Almost Is Never Enough" that it would snowball into what it's become today.

Now, not only is the love ballad a duet with The Wanted's Nathan Sykes, but also one of the songs featured on "The Mortal Instruments: City of Bones" soundtrack, alongside tracks by Colbie Caillat, AFI, Jessie J and Demi Lovato. When MTV News caught up with the singer, she broke down how it all came together.

"The version going on the 'Mortal Instruments' soundtrack is a much shorter version. The one that's on my [debut] album [Yours Truly, out September 3] is very long. But I'm really excited by it. And, honestly, I didn't know it was going to be a duet and [my manager] Scooter [Braun] just said 'Check your email'," she recalled, adding that a video will eventually be shot for it. (Braun also manages The Wanted.)

"And Nathan just sang the hell out of it. I thought it was Brian McKnight. I'm like 'Who is this?' Honestly I wasn't expecting it. I didn't know he had that in him. I saw him perform live on one of the radio shows that we were at together and I was like, 'Damn he can sing.' This song I think will pleasantly surprise a lot of people," she said. "It's very beautiful and very emotional and I love, love, love what Nathan did to it. It was a great, great, great surprise."

The surprises hardly ended there. Braun had one more surprise up his sleeve, the news that her track would be on the "Mortal Instruments" album, prompting an "Oh my god! Are you serious?" reaction from the 20-year-old singer and "Sam & Cat" star.

"It was very, very exciting. I'm just very excited for all of it. Music has been so important to me for so long, for my whole life. The time is finally here after a long, patient wait," she said. "And I am so incredibly thrilled to release this album and all this music."