There’s a piano in the ABBA Museum in Stockholm that mysteriously begins to play every now and then. No, it’s not haunted or a magic trick. The instrument is connected to Benny Andersson’s studio, and when he plays the keyboard there, whatever music he is making is duplicated — streamed, as it were — to the museum in real-time.

The keys must have been working overtime recently as the famed musician and co-founder of ABBA has been recording a new 21-track album, “Piano,” due out on the Deutsche Grammophon label on Sept. 29. The track listing is a journey through Andersson’s career, with songs from ABBA, the musicals “Chess” and “Kristina från Duvemåla,” Andersson’s solo albums from the post-ABBA 1980s and his more current work with Benny Anderssons Orkester (Benny Andersson’s Orchestra). “In a strange way, I feel like I am playing my memoirs,” says Andersson.

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“I try to write every day for hours on the piano,” says the famed Swedish musician who was inspired to keep playing the instrument at age 10 after hearing Elvis Presley’s “Treat Me Nice.” “Sometimes when I don’t know what to write, I play my own songs, like ‘Mountain Duet,’ ‘Anthem,’ ‘Chess’ or ‘You and I.’ This is where it all started, playing those songs made me think, maybe I should just record an album of me playing the piano. That’s what I have done. I thought I should do it for my grandkids.”

Andersson has appeared on a number of record labels throughout his career. In America, the earliest ABBA recordings, before the quartet was even named ABBA, were released on Hugh Hefner’s Playboy label, and then, beginning with “Waterloo” in 1974, on Atlantic. The group’s manager, Stig Anderson, had a strategy of signing ABBA to what he considered to be the strongest label in each territory, so their records appeared on labels like Epic in the U.K. and RCA in Australia.

“Piano” marks his first appearance on Deutsche Grammophon. “I’m really happy for it,” he says. “It is a very cool label, with their yellow logotype and it puts it in another drawer to everything else I’ve been involved with, so it feels good.”

It’s not a surprise that after all of his pop work, Andersson is appearing on Universal Music’s classical imprint. “I have primarily listened to classical music for the past 25 years,” he explains. “I don’t know at all what is going on in the pop scene. Pop music is for young people.”

“This new collection of solo piano recordings will reinforce Benny’s legacy as one of the finest contemporary composers of our time,” said Sir Lucian Grange, Chairman and CEO, Universal Music Group.

“These new interpretations offer a whole new perspective on his work,” added Frank Briegmann, president and CEO of UMG Central Europe and Deutsche Grammophon.”Benny has wowed and inspired his fans many times and in many different ways. And now he is doing it again.”

“Piano” was recorded with engineer and studio manager Linn Fijal at his RMV Studios on the island of Skeppsholmen, overlooking the waters of Stockholm. The first track, a new version of ABBA’s “Thank You for the Music,” is now available for download and via streaming services. Watch a teaser of Andersson performing the 1977 favorite below.