In June of 2015, the celebrated baritone Dmitri Hvorostovsky cancelled the majority of his engagements after being diagnosed with a brain tumour, in news that came as a significant shock to the opera world. Arguably peerless on today’s stage in the Verdi and Slavic repertoire that made his career, Hvorostovsky is beloved by colleagues and fans alike. It was with true affection then that those attending the Metropolitan Opera’s 50th Anniversary Gala greeted his surprise appearance halfway through the night’s festivities.

Met with sustained cheering and thunderous applause, Hvorostovsky blew kisses and opened his arms wide as if to embrace the whole audience, before squaring his shoulders and hunching down to give an energetic account of Rigoletto’s Cortigiani, vil razza dannata. Displaying his trademark legato and dramatic intensity, he received the audience’s bravos with more kisses, touching his heart in gratitude.

Though Hvorostovsky has given a number of recitals and staged performances since announcing his condition, his health has been unpredictable. Speaking to the New York Times, Peter Gelb, general manager of the Met, said that the baritone had his heart set on taking part in the gala. Hvorostovsky has been one...