Last week, Usher tried to perform in Berlin even though he felt ill. Unfortunately, the “OMG” singer was booed by fans for not being able to sing, let alone perform or dance. Usher's rep later revealed that Mr. Raymond is suffering from an “upper respiratory illness.” You can check out how visibly dazed he was in several videos on YouTube. He apologized in the following statement, “I deeply regret having to reschedule the shows. I am truly sorry for any inconvenience I have caused my fans. My fans are the best in the world and I am looking forward to getting better so that I can give them the show they deserve.”