[1] Born in Neusohl, (today Banská Bystrica in Slovakia), Hellwig made her debut at the opera house in Saarbrücken.
In 1938, she created the role of Ursula in Hindemith's Mathis der Maler at the Zürich Opera[2] which brought her international fame.
Hellwig was of Jewish faith and had to go into exile in the United States as the Second World War approached, before moving to Buenos Aires.
Among her other outstanding roles was the voice of the falcon in Strauss' Die Frau ohne Schatten,[3] conducted by Karl Böhm in 1955.
She also portrayed Judith very expressively, despite the Hungarian diction efforts she had to make for the role in Bartók's Bluebeard's Castle.