Kjartan Sveinsson is an Icelandic musician and composer, best known as a member of the band Sigur Rós. He played the piano and contributed to the band's unique sound, which blends post-rock with ethereal elements. Sveinsson was part of the group from its formation in 1994 until he left in 2013 to pursue other artistic endeavors. In addition to his work with Sigur Rós, Sveinsson has been involved in various musical projects and collaborations. He has explored different genres and styles, showcasing his versatility as an artist. His contributions have significantly influenced the Icelandic music scene and beyond.