In The Greatest Showman, Zendaya and Zac Efron share a soaring duet that quite literally defies gravity. Staged on a flying trapeze, the dazzling musical number ("Rewrite the Stars") is a real showstopper in the film, but the road to getting there was paved with bumps and bruises.

"I'm assuming it's quite literally like learning how to fly," Zendaya told MTV News of their intimate number. The scene finds Zendaya's young trapeze artist (Anne) and Efron's hotshot impresario (Phillip) tangled in an intimate, aerial cat-and-mouse chase on weighted ropes. And, yes, swinging in the air and making it look graceful is not particularly easy.

"We learned everything on the ground, and there's only so much you can predict and know on the day you're lifted up," Zendaya added. "It's like, 'I may crash into him! Who knows?'"

And crash they did. Many, many times. "You know the move where they grab each other and spin each other around?" director Michael Gracey said. "There are some very famous outtakes of them swinging in an just slamming [into each other] and just hanging limp. It's not graceful at all! And it looks incredibly painful."

"It was a lot of trial and error," Zendaya added. "A of things didn't work. A lot of things did work. But it was fun, though." And when the duo would find themselves stuck on a particular section, it was trapeze queen Zendaya to the rescue.

"She would be like, 'Well, what if I did this?' And she'd do a backflip over the hoop," Efron said. "We're like, 'Yeah, that fixes pretty much everything. Let's go with that. We didn't know you could do that.'"

Zendaya wasn't just influential during filming; the 21-year-old multi-hyphenate also played a significant part in the song's composition. During a pre-production workshop, Oscar- and Tony-winning duo Benj Pasek and Justin Paul, who composed and wrote all of the music for the whimsical movie musical, realized that "Rewrite the Stars" just wasn't working. Seeing as the number directly follows an emotionally heavy scene between Anne and Phillip, Gracey didn't want the moment to immediately transition into song; he wanted it to linger. So Zendaya suggested starting with a bit of a capella.

"She was like, 'Why does there have to be music?'" Pasek recalled. "And we were like, 'Well, there has to be music. It's a song!' Then we go to the corner, and we're like, 'Maybe she's right. It's kind of a good idea. Should we admit that?'"

Ultimately, it was the right call. It elevated the scene's emotional weight and captured the intimacy of two star-crossed lovers at a crossroads. "So we looked at Zendaya," he concluded, "and we were like, 'You're the queen of all things. You should be doing our jobs too.'"

The Greatest Showman is in theaters now.