Not while she was performing, but—

Metropolitan Opera diva Renée Fleming, in her autobiography, The Inner Voice:   The Making of a Singer describes a similar incident. It's been awhile since I read it, so I'm a little fuzzy on where she was and what she was doing, but she says that she had gone to "the little girl's room" to "freshen up" and was walking in a nearby garden when a man stepped up to her and said quietly, "Miss Fleming, I think you'd probably like to know that. . . ."

Yup. Back of her skirt tucked into the back of her panty hose.

Then she described how she went to see an opera performance, got there late, and tried to sneak in, being careful not to make any noise or cause a disturbance. Very dark, except for the stage. She sat down, gauging her location by the row of seats in front of her, forgetting that the seats were sort of staggered, so audience members could look between the heads of the people just in front of them. Pratfall! Landed with a resounding crash! People in the surrounding area leapt up to help her. At least one of them recognized her and said in a loud enough voice to reverberate through the opera house, "Miss Fleming, are you hurt!!???" Fortunately, nothing damaged but her pride.

Some days are like that.

Don Firth