The cathedral was completely empty due to the strict quarantine rules in the area.
"Thanks to the music, which is being streamed live, we unite millions of clapped hands worldwide and can hug the pulsating heart of the damaged earth," said Andrea Bocelli, according to AFP.
Bocelli was invited by Milan's mayor Giuseppe Sala and accompanied by an organist. The tenor sang four songs, including "Amazing grace," performed on the cathedral staircase along with a picture montage showing empty streets in Paris, London and New York.