SNL viewers may have enjoyed Rihanna’s performances last evening, but the audience for the show’s dress rehearsal — also performed last night, just before the live recording — didn't. The singer's reps confirmed to TMZ that "Rihanna was sick and needed to save her voice for the live show." Instead, her choreographer filled in for her. (After a sweet little penicillin shot from a doctor on call, she did feel good enough for the actual episode.) Such last-minute absences are very uncommon among SNL’s guest talent, and the show’s producers are said to be quietly annoyed.