There was a time a generation ago when Cecilia Bartoli's many U.S. fans could count on seeing her regularly in opera or in concert. The Italian mezzo-soprano noted for her warm sound, dramatic intensity and dazzling coloratura agility had shot to fame in the early 1990s while still in her 20s on the strength of best-selling recordings of Rossini and Mozart. Her every appearance just about guaranteed a sellout.

But that was then. She last sang at the Metropolitan Opera in 1998, hasn't been seen at Carnegie Hall since 2009, canceled a West Coast concert tour in 2015 and has stayed mostly in Europe, giving rise only to occasional rumors of an imminent return.  "You're right, it's time, it's time," Bartoli said in an interview earlier this month in Salzburg, where she was appearing in the title role of Handel's "Alcina."