Knud Torben Christensen (born 19 December 1949), better known by his stage name Sebastian, is a Danish singer, guitarist and composer. Starting as a musician in the late 1960s he is still active and very popular. So far his career has spanned four decades. Having worked in the folk genre, he has become one of the most prominent pop/rock musicians in Denmark and has scored numerous films and plays. Since the 1990s he has primarily worked with Danish musicals, with great success.