Benny Andersson and Bjorn Ulvaeus, the musical brains behind 1970s pop supergroup ABBA, have written their first new music together in 15 years.

Benny and Bjorn -- who represent the two Bs in the middle of ABBA -- penned "Story of a Heart", the title track in a new alburm by the Benny Andersson Band, according to a statement by Polydor Records, a division of Vivendi's Universal Music.

Much of the album is an excursion into Andersson's Swedish roots. "I wanted to make music based on the Swedish folk tradition, but with new songs written by me," he said.

Andersson plays accordion on the record -- something he has done since he was a six-year-old boy playing with his father and grandfather in Stockholm, according to Polydor.