Question: Clinton Marius, is a South African writer and performer, he made his first professional appearance singing the lead role in which opera in one act by Gian Carlo Menotti with an original English libretto by the composer?
Sentence (from "Amahl and the Night Visitors"): Amahl and the Night Visitors is an opera in one act by Gian Carlo Menotti with an original English libretto by the composer.
Relevant evidence: Yes