Knud Grabow Christensen, better known by his stage name Sebastian, is a Danish singer, guitarist and songwriter.
Sebastian started playing guitar in 1966, and started writing songs in 1967. Since having worked in the folk rock genre in the 1970s, he became one of the most prominent pop rock musicians in Denmark and has scored numerous films and plays. His releases have reached combined sales of over 2.5 million copies since 1971. His singing voice began weakening in the end of the 1980s, because of bad health. He is still active, and has made several popular albums. So far, his career has spanned more than five decades.