Chantelle, who prior to entering the house was known as a Paris Hilton impersonator, had been challenged with convincing the celebrity housemates that she was a member of a girl band called Kandyfloss.
The culmination of her mission last night was to ensure that, as the housemates ranked their level of fame by taking their places on podiums marked 1-11 in the garden, she was not ranked the lowest.
In the end, the housemates milled around in the rain arguing briefly over who should be number one. That honour went to Barrymore, before shuffling on to podium places in a more or less random order.
Chantelle hung around the bottom with the relative unknowns from the music world: Preston from indie band The Ordinary Boys and Maggot from Goldie Lookin' Chain, who took 10th and 11th place respectively and leaving ninth place for Chantelle.
After the podium mission was passed, Chantelle was told in the diary room that was no longer a "nobody" and was now a celebrity, as the other housemates watched her on a screen.
However, most housemates had already rumbled or suspected she was not quite who she said she was, because she got confused over what position Kandyfloss's "hit", 'I Want it Right Now', had achieved in the charts and, in her performance of the song to fellow housemates, she appeared not to know all the words.
"I was really suspicious of Chantelle. Lots of thinks didn't add up. I thought you'd put her in here for her to pretend to be a celebrity... but I'm over that now," Preston told Big Brother.
If she had failed her secret mission, she would have faced instant eviction.
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