She sang in Cairo in 1956 and at The Stoll Theatre in London in 1957. That same year, she replaced Maria Callas in "La sonnambula" at the Edimburg Festival to considerable acclaim. This was the start of long and distinguished international career, with appearances in Chicago, San Francisco, Buenos Aires, Barcelona, Moscow, Tokyo, etc. She made her debut at the Metropolitan Opera in New York, on October 13, 1965, as Cio-Cio-San in "Madama Butterfly" and sang there regularly until 1987.