Keltiska Duon’s repertoire comes from the rich Celtic folk music traditions of Ireland, Scotland and Wales, consisting of fiery jigs and reels as well as the lyrical melodies and melancholy of the ballads.

Early Scottish and Irish music - mainly from the 17th century and onwards, and performed in a "folkified" style - also has a natural place in the band's repertoire. In addition to purely traditional music, Keltiska Duon also highlights music by composers such as Turlough O'Carolan (1670-1738), whose music often tends to be categorized as folk music but which was in fact influenced the classical music of the time as well as the older Celtic folk music tradition. Keltiska Duon's arrangements are playful and put great emphasis on improvisation, but always with great respect for the roots and origins of the musical material.

Band members Jonas Liljeström (fiddle and vocals) and Billy Jones (guitar) are veterans on the Gothenburg music scene and have performed together for more than 30 years.