Max Martin & Shellback, superstar producers

Illustration by Andy Bunday

While Swift worked with Martin and Shellback before, on the albums, Red (2012), 1989 (2014) and Reputation (2017), unusually, they are the sole producers of Showgirl. The Stockholm sessions, Swift said, “felt like catching lightning in a bottle”. Not for the first time, the focus is now on the phenomenally successful but reclusive producers.

To say that Martin (real name: Karl Martin Sandberg), and Shellback (Karl Johan Schuster) have dominated the global music industry for the past three decades would be an understatement. Working together or separately, they have become the go-to producers for the international pop elite, generating hits for Ariana Grande, Pink, Harry Styles, Katy Perry, the Weeknd, and more.

Martin, 54, a five-time Grammy winner, worth an estimated $400m (£298m), helped launch the career of Britney Spears with Baby One More Time in 1998. He is on course to break the record for most Billboard Hot 100 No 1s held by Paul McCartney and John Lennon. He and one-time apprentice, Shellback, 40, were previously credited with helping Swift mastermind her switch from country to pop, with smashes such as We Are Never Ever Getting Back Together, Blank Space, Shake it Off and Bad Blood.

Music writer Caroline Sullivan is the author of the 2024 bestseller, Taylor Swift: Era By Era: The Unauthorised Biography. She told me that after 2024’s The Tortured Poets Department, Swift would have looked to Martin and Shellback to facilitate a “brighter” album. “Taylor would see them as having helped guide her during some of her happier times, and now she wants to be happy again,” she said. Sullivan also feels the collaboration bolsters Swift’s appeal to young audiences: “Max Martin and Shellback have basically done every poppy thing you can think of in the past 30 years.”

The producers appear to be what the New Yorker writer John Seabrook was referring to in his 2015 book, The Song Machine: Inside the Hit Factory, when he wrote that Sweden had become “a nation of songwriters endowed with melodic gifts, and who were meticulous about craft, but who were reluctant to perform their own songs”. Certainly, Martin and Shellback are part of the wider story of Swedish music, beyond Abba, Roxette, et al: exemplars of the staggering dominance of Swedish songwriting/production in the global pop firmament. They’ve established a sound, a template, an aural script for modern pop/dance-pop: clever, twisty, infectious, heard soaring everywhere, from US radios to UK dancefloors, to the Eurovision Song Contest.

What’s more, in an era of showman-DJ/producers in the style of David Guetta and Mark Ronson, the genial, bearded, softly spoken pair, both married with children, have maintained scrupulously low profiles. Blue-chip songsmiths they may be, but they remain conspicuously inconspicuous; studio-bound ghosts in the machine.

Raised in Ekerö, Stockholm county, and once in a failed glam-metal band called It’s Alive, Martin was among the proteges of influential producer Denniz Pop (real name: Dag Krister Volle) at Cheiron Studios in Stockholm. “I didn’t know what he saw in me,” Martin told the Guardian in 2023. Pop – who had huge success with Backstreet Boys, Ace of Base, and NSYNC – died of cancer at the age of 35, just as Spears went stratospheric.

As he had been nurtured by Pop, Martin mentored Shellback, a heavy metal drummer raised in Karlshamn, who adopted his nickname after a wise turtle character, Skalman, in a Swedish comic called Bamse. Initially a pop sceptic, by his early-20s Shellback (estimated worth: $50m) had co-written So What with Pink and Moves Like Jagger with Maroon 5.

In 2019, James Ballardie made a penetrating BBC film about Swedish music, Flat Pack Pop: Sweden’s Music Miracle. He said that, while characteristically declining to be interviewed, Martin appreciated how the documentary explored how Swedish culture, social codes and philosophy informed their sound. Everything from folk music to long dark winters engendering acoustic melancholy and poignancy, to government prioritising of musical education, to the Swedish love of balance. All fed into Martin’s fabled theory of “Melodic math”: choruses and melodies algorithmically designed to make listeners emotionally connect.

What about the F-word: as in “formulaic”? A word some music fans might flinch from. Ballardie believes it’s more of a flexible equation: “We talk about the Swedish-ness of the sound, but really, it’s an ultra-internationalist approach.” He refers to the homeware company, Ikea: “If they design a table, they look at every possible table design in the world to make the simplest, most efficient version. Everything is about simplifying.”

Another concept that tends to come up around Martin and Shellback, and Swedish music in general, is “Jante Law”: not believing you’re better than anybody else. Which would seem to explain Martin and Shellback’s understated approach to fame. It may also identify them as leading a certain school of non-ego-driven producers: crucial sounding boards for songwriters, providing an unsafe/safe space: designed to be safe enough for editing and mistakes, but dynamic enough for creativity.

Martin is thought to be taking more of a creative executive role these days, and to be involved with philanthropy, including co-founding the charity, MusikBojen, helping children with music therapy. In 2016, it took being awarded the Polar prize, the Swedish musical equivalent of a Nobel – previously given to Paul McCartney and Bob Dylan – to spur him into a rare public appearance. “You blew my cover,” he joked. “I managed to hide between my speakers in a basement for 20 years, and then you did this.”

It’s amusing to think of him and Shellback saying a version of this to Swift. Matching the world’s biggest popstar with the biggest music production phenomenon is hardly a rash creative gamble. Perhaps this is what the most stellar artists look for: sure “Melodic math”, but also guarantees.

Born Ekerö, Sweden

Real name Karl Martin Sandberg

Age 54

Work Songwriter and music producer

Born Karlshamn, Sweden

Real name Karl Johan Schuster

Age 40

Work Songwriter and music producer