“In the very beginning,” says Mark Ronson of what proved the most marathon effort of his musical career, “there were only going to be two songs.” Ronson, the artist and producer best known for his work with Amy Winehouse and the chart-smashing solo singles Uptown Funk and Nothing Breaks Like a Heart, had been approached about contributing a couple of tracks to Greta Gerwig’s Barbie film: one song for Barbie’s big dance number and another to shed light on Ken’s (not-so-rich) inner life. Those are now familiar everywhere as Dance the Night by Dua Lipa, and the unlikely hit I’m Just Ken, performed by Ryan Gosling. But, as momentum behind the project continued to build, it soon became clear: there was no putting Barbie back in her box. From two songs, Ronson’s responsibilities expanded to overseeing the entire Barbie soundtrack and scoring the film with Andrew Wyatt, his longtime collaborator. It turned out to be the biggest movie of the year, a cultural juggernaut that looks as if it will get a new lease of life at next year’s Oscars. Just as the film broke box-office records, its soundtrack is the most successful so far this century. It also became the first soundtrack to land three singles in the UK Top 5 at once, including Dance The Night (alongside Nicki Minaj’s Barbie World and Billie Eilish’s What Was I Made For?). The last time a soundtrack scored a hat-trick was Saturday Night Fever and Grease, both in 1978, and even those songs only made the Top 10. Appearing with Wyatt over video call from New York, Ronson remains stunned by its success. “It’s very, very, very weird,” he says. “There’s always a part of us that wants to write timeless pop bangers, but our prerogative, at the time, was to make the best songs for the film.” Having received his “marching orders” from Gerwig, Ronson’s first move was to hire Wyatt, the Miike Snow frontman with whom Ronson worked on A Star is Born, including Lady Gaga’s Oscar-winning hit Shallow. Their Barbie collaboration Dance The Night is similarly commanding: a shimmery slice of disco-pop, with the stylish orchestration and attention to detail that has made Ronson so in-demand as a producer. The challenge, he says, was making not just a dancefloor hit but one that supported the film. An early attempt was felt to be too knowing to suit that sunny early chapter of the film, preceding Barbie’s existential crisis. It wasn’t “marrying with what was happening on the screen: Margot Robbie in gold sequins, having the time of her life,” says Ronson. The lyrics were “a little more ambiguous”, adds Wyatt. So the duo went back to the drawing board – but they didn’t have long. The song was needed for the trailer and, in England – at Warner Bro’s Leavesden studios where Barbie was largely produced – choreography was already in progress. “We rewrote it twice,” says Ronson. After their punchy, arch first effort, the second felt “a little too anodised, like we had corrected too much”. Dance The Night came together at “the 11th hour”, says Ronson, with revisions needed to match the on-screen choreography. Then, days before it was due to be shipped for the trailer, they realised they had forgotten to replace the stopgap, synthesised instrumentation with the 80-piece orchestra they had recorded. “We did the strings the day before it went to mastering,” says Ronson. These last-minute saves prove to be a recurring theme of our interview, reflecting the many fast-moving parts of the production and the pair’s relatively low ranking within it. “They weren’t going to wait for the music,” says Wyatt. It was a shift in gears from their work in the pop world. “We’re usually working on either our own records or with big pop stars – if they want the extra two weeks, they’re going to get them,” says Wyatt. “With this … it just had to be ready.” The two of them worked on the film almost exclusively from March to June this year. For the final two months, says Wyatt, “We had to make ourselves available 24 hours a day.” For Ronson in particular – tasked with overseeing the entire soundtrack, involving 20 different artists – it was a monumental step up in administration. He recalls the “marathon, two-hour biweekly Zooms” with the record label Atlantic with a slight shudder. “But the movie was just so fun – there was no way that I wasn’t going to do whatever was asked of me at that point,” he adds. What helped, Ronson says, was the energy with which all the artists approached the task. The interpretations range from Eilish’s introspective ballad, to the winking, iron-pumping anthem by Sam Smith. It speaks to the richness of Barbie herself as a symbol, as well as Gerwig’s film. “Everybody just saw their scenes and was instantly bursting with ideas,” says Ronson. Some artists were already slated for particular moments, such as Charli XCX for the chase sequence and Eilish for the film’s emotional apex. Their songs were revised with test screenings. “There’s nothing like watching a movie in a room with other people to make you go: ‘Oh, fuck, this is a bit long,’” says Ronson. But the artists were given leeway to make a song that felt like their own. “Everybody did their own thing,” he says. “Nicki Minaj has been calling herself Barbie, and her fans the Barbz for ever, so of course that was going to be referenced. Charli instantly came up with that ‘Hey Barbie’ Mickey flip.” (He’s talking about Charli XCX’s Speed Drive, interpolated with Toni Basil’s Mickey.) “But everybody involved was so smart – whatever their take, we knew that it was going to be cool and interesting.” Only SZA was missing from his dream soundtrack lineup, Ronson admits when pressed; given who he did land, he frets that “it would be very ‘spoiled brat’” to complain. (Meanwhile, Ronson reveals that Gerwig’s first choice of musical collaborator was the Bee Gees’ Barry Gibb; he “politely declined”.) Given the range of artists featured, the Barbie soundtrack was never intended to be a cohesive whole, says Ronson – nor to be enjoyed without reference to the film. “Greta didn’t want to put anything in the movie that felt random.” The selection of Push by Matchbox Twenty – the late-90s alt-rock radio hit, criticised as misogynistic – as Ken’s favourite song was Gerwig’s idea, though Ronson reveals that Gosling messaged singer Rob Thomas to reassure him that they weren’t making fun. “I think Ryan just wanted to tell Rob Thomas that he didn’t represent toxic masculinity – but the song did work really well in the film.” Likewise the film’s other quasi-men’s-liberation anthem, Man I Am, was fleshed out between Gerwig and Sam Smith. “Sam and Greta started having this back-and-forth volley, talking about Betty Friedan and [her book] The Feminist Mystique. I just knew to shut up,” says Ronson. These brilliant comedy writers think our song is good enough to actually put into this script ... We kept building it out from there But Ken’s big musical number was left in entirely in their court. Ronson had the idea for the angst-ridden chorus lyric, “I’m just Ken, anywhere else I’d be a 10”, then Wyatt wrote the verses from the perspective of a lovelorn, overlooked himbo. Gerwig “flipped out over it,” says Ronson. “I remember she wrote back, saying: ‘Ryan says this song speaks to him very deeply’. I was like: ‘Was he being sarcastic?’ Because that’s a very emotional, heartfelt sentiment. She said: ‘I don’t think so.’” At that time, Gosling was not due to sing on the film – but Ronson and Wyatt’s work moved him. “The next thing we knew, Greta said Ryan’s down to sing it, and we are going to rewrite this battle scene to incorporate it.” Ronson still seems chuffed: “These brilliant comedy writers think our song is good enough to actually put into this script … We kept building it out from there.” From two-and-a-half minutes, I’m Just Ken was expanded into a seven-minute, wonderfully over-the-top power-ballad. Guitarist Wolfgang Van Halen, Foo Fighters’ Josh Freese and Slash of Guns N’ Roses, who deemed the song “cool”, were roped in to play. For Ronson and Wyatt, that step towards musical theatre was their prompt to volunteer to take charge of the score as well as the soundtrack. The opening number Pink, in which Lizzo narrates Barbie’s goings on on-screen, also came together at the 11th hour, in stops between Lizzo’s world tour. “It was definitely a good sport of her, to write to this exact piece of music,” says Ronson. He had feared having to go to Gerwig empty-handed. “Then Lizzo just started freestyling. We were just goofing around and I was like: ‘OK, if the three of us are laughing …’” It was all very seat-of-the-pants for a known perfectionist like Ronson: “We could have used six more months,” he says. But both look back fondly on their pink-washed project. “I have a visceral memory of showing up to the studio every day and firing up the TV. Every single freeze-frame of this film was like a painting,” says Ronson. “Every day was a little bit of a joy.” He is now back to writing his first book, 93 ‘Til Infinity, about his time DJing in New York in the 90s, as well as working on a solo album. Wyatt is also “back in the box”, at work on other projects. But they haven’t broken free of Barbieland entirely. “We haven’t taken the Barbies down in the studio,” says Ronson.