Pop star Mariah Carey has been appearing on television to apologize for her not-so-good performance at Michael Jackson's memorial service, because she feels she "let everybody down". Mariah was the first singer to take the stage at the Staples Center in Los Angeles California on Tuesday to mourn Jackson's sudden death. Carey sang the classic Jackson 5 hit "I'll Be There" at the service, but struggled to hit the notes and looked tearful throughout her set. Mariah then took to her page to apologize for her performance, and insisted she battled to hold back her sobs after spotting Jackson's gold coffin below the stage. And Mariah is still upset with guilt over her efforts, appearing on "Today" on Wednesday to explain her disappointment at the way she sang. She said, "I feel a little bit like I let everybody down, but I really did try and it was difficult." However, the Carey insists the embattled set showed just how much Jackson's passing had affected her. She added, "But you know what I think? It was a true and honest emotional moment."