Yikes! Mariah Carey’s Live “All I Want For Christmas” Rockefeller Center Performance.

Remember that one time when Mariah Carey could sing anything (including her own songs)? That day was not yesterday when she sang her Christmas song "All I Want For Christmas Is You" LIVE at the Rockefeller Center Christmas Tree Lighting. 

TMZ has isolated the vocals and WHOA! What happened?

Here's the deal: It didn't have to happen this way. Mariah was scheduled to pre-tape her performance but she was being such a diva that after waiting 3 hours past their set time, production got tired of waiting. They told Mariah that her performance would be live.

This is exactly the reason they pre-tape performances like this.

If you were famous and had an opportunity to be a diva, would you take it?