Citing illness, mezzo-soprano Stephanie Blythe has had to cancel her performance tomorrow as Amneris in the Pittsburgh Opera's production of "Aida.''

She will be replaced in the 8 p.m. performance at the Benedum Center by Marianne Cornetti, a renowned performer from Western Pennsylvania who will fly in from Amsterdam, where she had been preparing to perform in another opera.

Blythe is expected to continue the run of performances, starting Tuesday.