Upshaw also canceled a performance at Florida State University on February 24, according to the Tallahassee Democrat. Leo Welch, the assistant dean of the university's music school, told the paper that he had been told that Upshaw had undergone surgery.
"Apparently, it's not life-threatening but it's something that needs to be done during the next couple of days," Welch said. "We're very disappointed, but this is something totally beyond her control. We wish her a speedy recovery."
The Kennedy Center performance was to feature songs by Dowland, Debussy, Rachmaninoff, Bart‹k, Weill, and William Bolcom.
Upshaw's manager did not return a phone call seeking further details.