Lys Assia

Lys Assia (born Rosa Mina Schärer, 3 March 1924, Rupperswil, Aargau, Switzerland) is a Swiss singer who won the first Eurovision Song Contest in 1956. When Lys Assia was a young girl she was a dancer. In 1940, however, she stood in for a female singer. People who heard her singing liked it, so she changed from dancing to singing.

source: Wikipedia