U.D.O. are a German heavy metal band from Solingen. Formed in 1987 by eponymous vocalist Udo Dirkschneider following his departure from Accept, the group originally included guitarists Mathias Dieth and Peter Szigeti, bassist Frank Rittel and drummer Thomas Franke. The band released their debut album Animal House before the end of the year, after which Szigeti, Rittel and Franke were replaced by Andy Susemihl, Thomas Smuszynski (after a brief tenure for former Accept bassist Dieter Rubach) and future Accept drummer Stefan Schwarzmann, respectively. Wolla Böhm replaced Susemihl for 1990's Faceless World, although by the time of the next album Timebomb, U.D.O. were a four-piece. In 1992, after touring in promotion of Timebomb, U.D.O. disbanded as Dirkschneider returned to the reformed Accept