Gillian McKeith admitted she was embarrassed by fainting on I'm A Celebrity...Get Me Out Of Here, describing the show as being "like a horror movie that never ended".
The 51-year-old nutritionist said she had never watched the hit ITV1 show before because of her phobia of insects.
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She told Heat magazine: "It was like a horror movie that never ended. People are looking for this incredible explanation and I really don't have one. I liked the idea of going to Australia and thought I'd get a bit of a holiday.
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"There's no doubt that I didn't completely understand what I was getting myself into. I thought it would be an interesting way of challenging myself. When I finally realised what I was facing, I was absolutely mortified."
She also defended herself against claims she faked her fainting episode when she collapsed after being chosen to take part in a bushtucker trial.
McKeith, who struggled to deal with life in the jungle, said she had "a history of fainting".
She said: "The first time I fainted - and it sounds quite hilarious - was when I got very excited because I thought I saw Santa Claus. All I can say to people is that I've got scoliosis, and there's no way in a million years I can risk banging my back. I've probably fainted 12 to 15 times in my life. It has to be something pretty intense.
"The whole thing was an embarrassment. The worst thing was fainting on TV - I can hardly bear it."
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