Rihanna canceled her Grammys performance right before the show, citing illness.

“Based on Rihanna’s examination, after Grammy rehearsal today, Rihanna’s doctor put her on vocal rest for 48 hours because she was at risk of hemorrhaging her vocal chords,” her rep told Page Six on Monday night.

Her rep added, “The antibiotics she has been on for three days did not kill the infection adequately. Therefore she cannot perform safely.”

But a spy quipped to us, “It was a mediocre performance during rehearsals anyway. She rehearsed twice.”

She was supposed to be the fifth performance of the night, singing “Kiss It Better” off her newest album “ANTI.”

TMZ first reported the news.

This article originally appeared in the New York Post's Page Six.