It's been a rough two weeks for Whitney Houston, as she and her depleted voice battle through a British tour that has been dominated by poor performances, unmerciful reviews and bummed-out fans. The multi-Grammy winner even acknowledged her shortcomings to concert-goers Sunday night in London after an off-key rendition of her biggest song, 'I Will Always Love You.'

"She don't want to come, my soprano friend," Houston, 46, said of her instrument after croaking her way through the soaring section of the hit.

She added: "Sometimes the old girl sings, but not tonight. I want to do it, but she doesn't want to ... She's getting a little ... temperamental, even."

London, 4/26

Birmingham, 4/13