It wasn’t long after Mark Ronson signed on to executive produce the Barbie soundtrack that he learned the first lesson of living in the doll’s candy-coated world. He was standing in the aisles of Toys “R” Us one morning, buying up Barbies for his studio, when he realized, “You cannot find a Ken doll for love nor money in any Toys ‘R’ Us, because nobody gives a shit about buying a Ken doll.” So he texted Mattel CEO Ynon Kreiz, who had a few of the plastic hunks sent over. “I haven’t been back in my studio in a while, so they’re still here,” Ronson says as one smiles at me from the edge of the Zoom screen.

When the seven-time Grammy winner first read Greta Gerwig and Noah Baumbach’s Barbie script, he immediately connected with the Ken they’d written for Ryan Gosling to play. “You really fall in love with this hapless, but immediately sympathetic figure,” Ronson says. “I instantly had this idea for this lyric: ‘I’m just Ken / Anywhere else I’d be a 10.’ It just seemed funny. It felt a little bit emo, like, this poor guy. He’s so hot, but can’t get the time of day.”

“She’s everything. He’s just Ken” is now plastered across billboards and subway stations as the days tick down until Barbie’s July 21 premiere. “It’s sort of wild,” says Ronson, who adds that he had no clue that Barbie would become the movie you can’t escape this summer.

Stars Margot Robbie and Gosling have been on a never-ending press circuit. Twitter can’t get enough of the movie matchup dubbed “Barbenheimer.” Barbie-branded merchandise is flooding the internet. When Barbie: The Album drops the same day the Gerwig-directed film hits theaters, it’s going to be everywhere too. Spotify users have already been adding Dua Lipa’s disco pop anthem “Dance the Night” to playlists and sending Nicki Minaj and Ice Spice’s “Barbie Girl”–laced “Barbie World” to number seven on the Billboard Hot 100 chart. There are also songs from Lizzo, Charli XCX, Tame Impala, Haim, and, it was recently revealed, Billie Eilish and Sam Smith.

Ronson’s work on Barbie began with “Dance the Night”—and once he entered Barbie’s dreamland, it was hard to leave. He ended up scoring the film alongside frequent collaborator Andrew Wyatt. “Greta proves that you can be an incredibly strong-minded visionary, but inspire people by just your goodness alone,” Ronson says. “I think that was what enabled not just me and the couple of songs that I did, but everybody who came in and made a song. Everybody just felt so free to create.” Below, Ronson breaks down how some of Barbie The Album’s biggest tracks came to be.

The text message that kick-started the whole project just read: “Barbie?” As soon as Ronson found out that Gerwig and Baumbach were attached, he says, “I was like, holy shit, I’m being asked to sit at the cool kids table.” He calls the script “so fucking genius and funny,” and says he was on board immediately.

His first task: write a dance track so catchy it could carry a whole scene in the film. To get Ronson into the right headspace, Gerwig made him a playlist full of disco, obscure Broadway tracks, and light, catchy music he’s dubbed “Peloton pop.” Production was set to begin in just two weeks, so Ronson put together a song without any lyrics that he titled “Tastes Like Barbie” and sent it off to Gerwig.

“Because it’s Barbie, the instinct is to go to something a little Euro and sugary, and that’s just never what I do,” he says. Instead, he wrote something that he describes as “definitely disco and you can groove to it, and it’s definitely gold and sequin-y, but it’s got a really tough driving thing to it.” It didn’t take long for Gerwig to text back “like, you know, seven pink heart emojis,” with a message that she loved the song.

Lipa was Ronson’s first choice to write the lyrics and “give it an identity and a presence,” he says. The singer ended up hitting it off so well with Gerwig that she appears in the film as Mermaid Barbie.

When Ronson first wrote the lyric “Is it my destiny to live and die a life of blond fragility?” he wasn’t imagining that Gosling would be singing the song. He was just hoping that Gerwig and Baumbach wouldn’t laugh in his face. “When I sent the demo, I kind of mumbled that line, because I was like, if they don’t like it, I don’t want Greta and Noah to think that I’m trying to provide the funny.”

But Gerwig was a fan, and soon she passed along the message that Gosling was too. In fact, he related to the song so deeply that he asked to perform it in the film. To accommodate the request, Gerwig rewrote an important scene late in the movie—and asked Ronson and Wyatt to write a score that would lead into the song. (Eventually they agreed to write the score for the rest of the film too.)

Ronson flew to England to record Gosling’s vocals. Though he knew Gosling could sing—he was a Mouseketeer, after all—Ronson said he imagined having to adjust the key down to fit the actor’s “subdued baritone.” But not only did Gosling hit all the notes, he brought an emotionality to the performance that Ronson didn’t anticipate. “He really got [that] it had to walk this line of not being funny or parody,” he says. “But obviously, the song is also kind of ridiculous at times. So he was really amazing, and when he really did start hitting the big notes, I was like, this dude is a vocal powerhouse!”

From there, Ronson decided to “take it all the way,” bringing in Slash and new Foo Fighters drummer Josh Freese to play on the track. Warner Bros. gave fans a sneak preview of Gosling’s performance on the rock power ballad in a new teaser for the film.

Sometime after Ronson finished working on “Dance the Night” and “I’m Just Ken,” Gerwig asked him to put together the rest of the Barbie soundtrack. Ronson didn’t hesitate to say yes. “I just loved this film already so much, and I wanted to have as much to do with it as possible,” he says. So the duo sat down and dreamed up a list of possible collaborators. Ronson figured they’d be lucky to get a third of them, but as soon as the first photos leaked from the Barbie set, he found it wasn’t hard to convince people to come to his studio and watch a few scenes from the film.

Each time an artist would visit Ronson’s studio, he would hand-select a scene for them to watch to help inspire a song. When Lizzo came in, she was shown the opening credits. Originally Ronson and Wyatt had written a piece of music to play over the scene, which depicts a perfect day in Barbie World. He describes it as a “Dave Grusin, ’80s, Working Girl, Tootsie kind of thing,” and he thought it was pretty cute. But the four-minute sequence was calling out for some lyrics.

It wasn’t an easy scene to write a song around, because so much was happening on the screen. Ronson says Lizzo tried a few things, but nothing was quite working until she asked to watch the footage again. As the tape rolled, she began to freestyle over the beat, essentially narrating the action. “She said a couple things that just made me laugh out loud,” he recalls. Now, Ronson says, the film opens with “Lizzo basically welcoming you into the world of Barbie.”

The 17-song soundtrack features an eclectic mix of musicians, from Charli XCX—who sampled Toni Basil’s “Mickey” on “Speed Drive”—to Karol G to Khalid. But Ronson knew it wouldn’t be complete without Minaj, queen of the Barbz, or Aqua’s “Barbie Girl,” which Robbie was adamant be included in the film. It was a double victory when he found a way to combine them into one track.

First Ronson got producer RiotUSA to find a clever way to flip the chorus of the bubblegum pop hit. Then the producer connected Ronson with his regular collaborator: on-the-rise rapper Ice Spice. It was Ice Spice who helped get the track in front of Minaj. “And that’s how we managed to make the impossible possible,” Ronson says. “If you told me at the beginning of this movie that we were gonna get Nicki Minaj rhyming over a drill flip of ‘Barbie Girl,’ I’m like, then we’re good. We could just have 13 blank songs on the rest of the soundtrack.”