Harry Styles wrote the 'Do not Worry Darling' 'Trigger Song' in five minutes

Harry Styles was on "Late Night Talking" with his "Do not Worry Darling" director Olivia Wilde talking about the film score.

It turns out that the script for the psychological thriller only mentioned a "trigger song" that follows Styles' character Jack and his wife Alice (Florence Pugh) as they make their way through a gritty 1950s suburb.

"In preparation, Harry called me and asked, 'What's the trigger song? What's the tune?" and I said, 'I do not know.' I am going to different writers to write it. Do you have something in mind?'" director Wilde revealed to Variety. "And he said, 'I'll think about it.' Five minutes later he sent me a demo of his piano, and that's what ended up in the movie.

Wilde added, "He called me and said, 'How about this?' And I said, 'Yeah, that's it. That's it. And that's really crazy that you did that in five minutes.'"

Styles wanted to write "something that could be both sweet and creepy, depending entirely on the context," much like the film itself.

"I remember the first time I played the song on the piano and it felt like a homemade nursery rhyme," Styles shared. "Transferred to the different moments in the film, I think it takes on a few different lives - I hope."

And although the Grammy winner does not sing in the film, he does dance on the tape. "I feel like I have been waiting my whole life for someone to ask me to do a 35-second tap number," Styles joked.

The "Watermelon Sugar" singer originally replaced Shia LaBeouf in the film. The "Dunkirk" actor's performance on set even led director Wilde to cry tears of joy due to his passionate intensity as Jack.

"Harry took it to another level," Wilde told Rolling Stone. "He was so much in the moment that he started screaming the lines into the crowd with this primal roar that was much more intense than anything we expected from that scene."

Wilde continued, "We were all stunned by the monitor. I think even Harry was surprised by it. Those are the best moments for an actor - when you are completely out of your body."