The actress/singer was due to make an appearance at the 2013 National Association for the Advancement of Colored People (Naacp) Image Awards, where she was nominated for the Actress in a Comedy Series prize.
However, she fell down a flight of stairs on Wednesday (30Jan13) and didn't recover in time to attend the show.
She wrote in post on Twitter.com, "I am so clumsy, took an unexpected trip down my stairs smh (shaking my head) very sore little banged up but I'm okay..." before later adding, "My little fall was a little worse than I thought, was sad to miss the Naacp Awards... but I am so honoured to have been nominated!"
Riley went on to congratulate the eventual winner, Cassi Davis, who took the trophy for her role in Tyler Perry's House of Payne. She added, "Congrats (sic) Cassi Davis!... She's amazing."