Udo Dirkschneider (born 6 April 1952, Wuppertal, Germany) is a German heavy metal vocalist who is best known as the vocalist in German heavy metal band Accept and later U.D.O., the latter of which he formed after leaving Accept in 1987.Dirkschneider made a guest appearance on Eurovision Song Contest winner Lordi's 2006 album, The Arockalypse. Mr Lordi claims both "Don't Look Back" and "Blitz of Lightning" by U.D.O. as songs that changed his life in a Kerrang! magazine article.