sentence: on 21 november and 22 , bocelli was amongst a quartet of soloists ( soprano sabina cvilak , mezzo-soprano kate aldrich and bass alexander vinogradov ) to sing rossini 's petite messe solennelle , conducted by plácido domingo , at the washington national opera in washington , d.c. bocelli sang twice in the piece and later the two famous tenors sang '' the pearl fishers ' duet '' which would be the first aria they had ever sang together .