text: Among other artists who have performed in a non-competitive manner are Danish Europop group Aqua in , Russian pop duo t.A.T.u. in , and American entertainers Justin Timberlake and Madonna in  and  respectively. Other notable artists, including Cirque du Soleil (), Alexandrov Ensemble (), Vienna Boys' Choir ( and ) and Fire of Anatolia (), also performed on the Eurovision stage, and there have been guest appearances from well-known faces from outside the world of music, including actors, athletes, and serving astronauts and cosmonauts. Guest performances have been used as a channel in response to global events happening concurrently with the contest. The  in Israel closed with all competing acts performing a rendition of Israel's  winning song "Hallelujah" as a tribute to the victims of the war in the Balkans, a dance performance entitled "The Grey People" in 2016's first semi-final was devoted to the European migrant crisis, the  featured known anti-war songs "Fragile", "People Have the Power" and "Give Peace a Chance" in response to the Russian invasion of Ukraine that same year, and an interval act in 's first semi-final alluded to the refugee crisis caused by the aforementioned invasion.
  Criticism and controversy
  The contest has been the subject of considerable criticism regarding both its musical content and what has been reported to be a political element to the event, and several controversial moments have been witnessed over the course of its history.