The 1977 Eurovision Song Contest took place at London's Wembley Conference Centre but was postponed for five weeks due to a strike by cameramen and technicians, moving from April 2nd to May 7th. 18 countries participated. Sweden returned, while Yugoslavia withdrew. Tunisia was also set to make its debut but withdrew its entry before the contest. The rule requiring participants to sing in their national language was reinstated. However, Germany and Belgium were granted an exception to perform in English because their entries had been selected before the rule was changed. Germany's entry, "Telegram" by the popular group Silver Convention, was highly anticipated but only finished in 8th place. Other notable acts included Austria's Schmetterlinge, who performed "Boom Boom Boomerang" while wearing masks on the backs of their heads, and Anita Skorgan, who made her debut for Norway with the song "Casanova".