Today, Kingdom Hearts III — the 11th game in the long-running Square Enix and Disney franchise — is out worldwide. Music has always been integral to the series, and composer Yoko Shimomura has worked on every release. But more recognizable than the compositions are the main games’ theme songs, which, for the last two installments, have been written and recorded by the Japanese pop singer Utada Hikaru. (If you’re a Kingdom Hearts fan, hearing the opening notes to Utada Hikaru’s song “Simple and Clean,” the theme from the first game, will shove you directly into your feelings.) Tetsuya Nomura, the game’s director, brought Hikaru back to create a third theme song for the series, and she brought along Skrillex, the legendary electronic producer and former post-hardcore singer.

“It sounds kind of crazy, but I always said ‘I want to do the theme for Kingdom Hearts one day,’” Skrillex (aka Sonny Moore) says. “I told myself that as a kid. I was just such an absolute fan of Utada Hikaru and the games, but that was like a dream of mine.”

In 2013, Moore was playing a heavy metal festival in Germany. After a set, he went to the artists’ lounge, where Jack Black and Frankie B were hanging out. “I got a little tap on my shoulder, and I turn around, and this girl’s like, ‘Hey, you’re Skrillex,’” he says. “And I’m like, ‘What’s your name?’ She’s like ‘Utada.’” They kept in touch. Two years ago, they were catching up on the phone when Utada told Moore she was doing the new theme for Kingdom Hearts III. Maybe, she said, he could do a remix of it. She sent over “Don’t Think Twice,” which was originally supposed to be the game’s main song.

“I love the song, but it was like... I would put it in, and load it up in my Ableton Live, where I produce music, and I didn’t really know what to do with it,” Moore says. “It was really hard to touch because I just liked it how it was.”

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Things languished until last summer when Moore was working in London with his friend and collaborator, the producer Poo Bear (aka Jason Boyd). Utada happened to be in town. “And I’m like, ‘Yo, what if we just tried to write a new song for the game?’” he says. They went to the studio. “I started with these piano chords, and we wrote it in about an hour.” It was everything he expected, Moore said. While he was making the track, Moore soundtracked his work with the old game trailers. “I was actually editing and like composing the drop and the beat to all that stuff.”

“I’m really sensitive to the game, you know, and wanted to do it justice,” Moore tells me. “I was really happy with the result.” The song was recorded and mixed a year before it ever saw the light of day, which was a challenge. “I’ve never finished a record and mixed it and had it had to sit for like a year. As a producer, I want to like, redo things, make things sound better.”

Moore’s been a fan of Kingdom Hearts forever, and he says he’s beat both of the previous console games, Kingdom Hearts and Kingdom Hearts II. “I just really think it’s a perfect sort of blend of action and RPG,” he says. “It’s like a fantasy” as though “what if fucking Batman and like... Spawn had a movie together.” But even though he’s a fan, and even though he produced Kingdom Hearts III’s theme song, Square didn’t give him a copy of the game. “They didn’t give me that shit yet,” he says. “I’m on the waiting list just like everyone else.”