MOSCOW (AP) — Beloved Russian baritone Dmitri Hvorostovsky has died after a long battle with cancer. He was 55.

Diagnosed with a brain tumor in 2015, Hvorostovsky had all but given up live performances. In June, the Vienna State Opera announced that he had cancelled all upcoming appearances.

The acclaimed singer "died peacefully" early Wednesday morning and was "surrounded by family" near his home in London, his office said in a statement.

"May the warmth of his voice and his spirit always be with us," the statement said.

One of the most prominent opera singers of his generation, Hvorostovsky topped the billed at the world's leading opera houses.

The opera world cheered in May when Hvorostovsky made a surprise appearance at a Metropolitan Opera gala to sing an impassioned account of Rigoletto's big solo, "Cortigiani, vil razza dannata," one of his trademark parts. Hvorostovsky's elegant, burnished voice that had been heard at the Met 182 times before brought some in the audience to tears.

Outpourings of grief were coming from all over Russia on Wednesday.

"It's a disaster," Vladimir Urin, director general of the Bolshoi Theater, told the Tass news agency. "The person with a wonderful voice, unique musicality and an incredible artistic ability has passed away."

Urin said he had invited Hvorostovsky, who had never sung at the Bolshoi, to make an appearance but that never happened.

Born in Siberia's Krasnoyarsk, Hvorostovsky embarked on a successful career in the West in the late 1980s. He was also known and loved at home for performing World War II-era classics.

"He was an absolute raw talent, an absolutely, incredibly kind soul," Russian pianist Denis Matsuyev said in comments to the RIA Novosti news agency. "I would call him a Siberian knight who broke through onto the global stage."

The Kremlin offered its condolences to Hvorostovsky's family on Wednesday with presidential spokesman Dmitry Peskov calling the baritone "a treasure not only of the Russian but also world culture."

Hvorostovsky is survived by his wife and four children.