March 15, 2010 -

Rihanna understands why organizers didn't ask her to perform at the upcoming Grammy Awards - after her bust-up with ex Chris Brown forced her to pull out of the 2009 event.

Both stars were due to sing at the prestigious ceremony in February 2009 but they canceled their slots at the last minute after Brown left Rihanna battered and bruised. The Umbrella hit-maker has since returned to the spotlight by releasing her fourth album, Rated R, in November and fans had called for her to seal her comeback with a slot at the 2010 Grammys.

However, Rihanna insists she won't be taking the stage after she and Brown caused the producers so much hassle last year. She says, "We messed their show up pretty bad last year. They might be a little mad at me."

The 21 year old is expected to attend the event, which takes place in Los Angeles on January 31st. She is nominated for two awards for Run This Town, her collaboration with Jay-Z and Kanye West.

Michael C. Hall had plenty to celebrate Saturday night.

Just a week after winning a Golden Globe for his serial killer star turn on Showtime's Dexter, the actor was named outstanding actor in a drama series at Saturday's Screen Actors Guild Awards. And, he told PEOPLE backstage, his cancer is in remission.

"I'm two-thirds of the way through this treatment that already has this thing in remission," he said. "It's nice in the homestretch to have this kind of shock of positive energy. It's a celebration."

Hall, 38, who is very private, initially said he revealed that he was being treated for Hodgkin's lymphoma, because he knew he would be making several public appearances. "Because award shows were imminent, I had to make a statement," he said at last week's Globes.

As it turns out, there has been one unexpected and positive result of his admission. "I've been feeling very well," he told reporters backstage at the SAG Awards, "because I made this announcement. Because of these public events, I've heard from people I would have not have heard from otherwise."