Whitney Houston Misses High Notes at London Concert
LONDON, ENGLAND - APRIL 25: Whitney Houston performs at 02 Arena on April 25, 2010 in London, England. (Photo by Matt Kent/WireImage) *** Local Caption *** Whitney Houston Matt Kent/WireImage

It's safe to say that Whitney Houston was not at her best this Sunday (Apr. 25) during her sold-out concert in London's O2 arena. According to several negative reviews and fan accounts, the singer failed to hit the high notes she's known for during most of the show -- and the low point reportedly came during an unfortunate version of "I Will Always Love You" that saw fans heading for the exits.

Video: Whitney Houston performs "I Will Always Love You"

Houston was upfront about her voice troubles after singing "I Will Always Love You," saying, "She don't want to come, my soprano friend...sometimes the old girl says, 'Not tonight. I'm not doing it.' I want to do it, but she doesn't want to. I've had long talks with her about it. Tonight she's feeling a little [inaudible]...temperamental, even."

The U.K.'s Daily Mail called the show "memorable - but unfortunately for the 20,000 fans, for all the wrong reasons," while the Evening Standard tore mercilessly into Houston's performance. "There is no skirting around this: that fabulous voice is utterly, utterly torn to shreds."

Video: Whitney Houston performs "I Will Always Love You" (ctd.)

Earlier this month, Houston rescheduled the opening dates of her U.K. tour -- her first in 11 years -- due to an upper respiratory infection. The news followed her February trek in Australia, where the R&B diva was also panned by some critics and fans. Her publicist Kristen Foster issued a statement at the time denying Houston was having health problems and insisted she was having a "terrific time on her tour and with her fans."

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