Camilla Williams, the first black woman to perform with a major US opera company who became both a cultural ambassador and civil rights activist, has died aged 92.

All my people sing. We were poor, but God blessed us with music

“She died at home of complications from cancer,” said Alan Barker, a spokesman for Indiana University’s Jacobs School of Music where Ms Williams taught for 20 years.

Born in Danville, a small town in the segregated southern state of Virginia, Ms Williams began her singing career in a church and was introduced to the classical repertoire at the age of 12 when a Welsh voice teacher came to visit.

“All my people sing. We were poor, but God blessed us with music,” Ms Williams said.

She supported herself by working as an usher while taking voice lessons in Philadelphia and landed work on RCA’s national radio show The Music America Loves best in 1944 and as a soloist with the Philadelphia Orchestra.

She made her legendary debut with New York City Opera in the title role of Madama Butterfly in 1946 and was hailed by the New York Times as an instant success who had a “vividness and subtlety unmatched by any other artist who has assayed the part here in many a year”.

Ms Williams began a distinguished international career in 1950.

That same year she married Charles Beavers, an eminent civil rights lawyer who once represented Malcolm X.

She sang at the 1963 March on Washington just before Dr Martin Luther King Jr gave his monumental “I Have a Dream” speech and again when he was awarded the Nobel Peace Prize a year later.

Ms Williams also became a frequent cultural ambassador, invited by President Dwight Eisenhower to perform for the Crown Prince of Japan in 1960 and embarking on tours of Africa, Asia and Europe at the request of the State Department.

She retired from the stage in 1971 and became a professor of voice at Brooklyn College. She joined Indiana University in 1977 and taught there until 1997.