The former stars of The Hills will be the unwitting stars of the 'Big Blogger' task, visiting the Diary Room under the pretence of a live online chat with a competition winner.
Heidi and Spencer will be told they have won a public poll to answer questions for the CBB-based internet show Big Blogger and will meet members of the online team who will film the event.
In reality, the pair will be viewed by the other housemates as they're interviewed for the fictitious series. After watching the interview for the 'show', housemates will pose as the competition winner and feed questions to the couple.
The others will be tasked with finding out specific information, including Heidi and Spencer's opinions of the housemates, their feelings about controversial incidents in the house, explanations for their behaviour so far in the series and their thoughts on evictions and nominations.
If housemates are successful in quizzing Spencer and Heidi, the housemates will win a reward.
Photo gallery - Celebrity Big Brother day 15:
Copyright: Channel 5