Zayn and Taylor Swift sent the world into shock when they dropped the most unlikely collaboration late last week (December 9) titled "I Don't Wanna Live Forever" for the 50 Shades Darker soundtrack, leaving us all to wonder: How, exactly, did this bizarre pairing come about?

Well, wonder no longer! Zayn revealed the mechanics behind his duet with Taylor during an interview on the Elvis Duran Show this morning (December 13).

"We were kind of in separate places when I mentioned the idea to her, I spoke to her on the phone," he said. "She had heard the song 'cause Jack [Antonoff] had played it to her, so she really liked it. She went in the studio the next day — I think she was somewhere else, I can’t remember exactly where she was."

Zayn continued, noting he wasn't intimidated by the thought of asking the world's biggest pop star if she was interested in collaborating, because she'd already expressed interest in the track.

"The interesting thing was she’s actually friends with Gi[Gi Hadid]," the Mind of Mine singer continued, "so she’d already reached out cause Jack had played her the song anyway, just cause we’d done it together and she really liked it and she mentioned to me that she liked the song so I already kind of knew in the back of my head that she liked it. So I asked her if she could be on it and she was cool with it."

Zayn also touched briefly on the writing process behind his recent book release Zaynnoting he doesn't regret its personal nature.

"We kind of did it over an interview process thing, so we had a person that would prompt questions and ask for stories," he explained. "And we would just write down memories and then just go through that and see what made the most sense chronologically."

The "sHe" singer says the book offered him significant catharsis, and he's happy with the way it came together.

"I feel like writing anything down is kind of a little bit of a therapy process," he said. "It’s just a way of alleviating something that’s on your mind and getting it out there. So for me it was kind of a little bit of that, and I enjoyed it. It was fun to reminisce on things and think of what was bad and what was good and make sense of it all, because I didn’t feel like I really had time to do that in the band."

Check out Zayn's full interview with Elvis Duran in the video above.

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