Los Angeles -
R&B superstar Rihanna abruptly cancelled her performance at the Grammys, the music industry's top awards, citing vocal problems due to illness.
Rihanna was spotted entering the Staples Center in Los Angeles, but the ceremony went ahead, skipping her performance.
"So sorry I couldn't be there," Rihanna wrote to her more than 56 million Twitter followers, thanking the Grammys and broadcaster CBS.
A representative for the Barbados-born singer said that she left on doctor's advice.
"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 cords," the statement said.
"The antibiotics she has been on for three days did not kill the infection adequately. Therefore she could not perform safely," it said.
Rihanna, who is due to start a global tour later this month, was scheduled to sing "Kiss It Better" from her new album "Anti."
In one of the most notorious incidents in recent Grammy history, Rihanna was forced to cancel her performance in 2009 after she was beaten up by her then boyfriend, rapper Chris Brown, who later pleaded guilty to a felony.