Taylor Swift wowed fans on the third night of her Eras Tour in Stockholm with a heartfelt tribute to Swedish music maestro Max Martin, transitioning from celebratory to somber moments with her acoustic performance and the live debut of “How Did It End?” from her latest album, ‘The Tortured Poets Department: The Anthology.’

Taylor Swift dedicated her acoustic guitar mash-up to Max Martin, the Swedish record producer and songwriter, on Sunday (May 19). Taylor Swift’s surprise song set transitioned from celebratory to somber in Stockholm. During the acoustic section of her Eras show at Friends Arena, Swift beamed with joy as she dedicated a medley to Sweden’s Max Martin. However, her mood turned melancholic for the live debut of “How Did It End?” from The Tortured Poets Department: The Anthology.

“Max is actually here tonight, but he’s a shy genius so I’m not going to bring him out onstage but I am going to what I am calling the ‘Max Martin Medley,’ ” she told the fans at the final night of her Eras Tour in Sweden, Stockholm.

Swift combined “Message In A Bottle” from “Red (Taylor’s Version)” — the first track she collaborated on with Martin — with “How You Get The Girl” and “New Romantics” from “1989 (Taylor’s Version)” in her guitar mash-up.

As fans cheered for the five-plus-minute acoustic song, the wristbands in Friends Arena alternated between bright red and turquoise, lighting up the venue.

However, the atmosphere took a somber turn when Swift sat at her piano and addressed the crowd, saying, “I’ve never performed this one live before,” before launching into “How Did It End?” from Tortured Poets. This stirring ballad, featured on the Anthology edition of her new album, delves into the collapse and end of a relationship.

When the European leg of the Eras Tour began in Paris earlier this month, she introduced “Tortured Poets” tracks into her set list and implemented other modifications to the show. The tour recently arrived at Friends Arena in Stockholm, temporarily renamed “Swiftholm” for the occasion, on Friday.

After attending her 87th Eras Tour performance in Paris, fans didn’t catch sight of Taylor Swift’s boyfriend, Travis Kelce, in Sweden. Kelce instead hosted a music festival called Kelce Jam on Saturday night in Bonner Springs, Kansas.

After a three-day run in Stockholm, Taylor Swift will bring her Eras Tour to Lisbon, Portugal, for a series of concerts next weekend.