The group will this afternoon discover nine 'letter bombs of love' in the living room, each of which contains a message from one contestant's friends and family.
The devices are rigged to blow at random points throughout the day and the housemate in question will be required to disable it within a time limit in order to save their note from destruction.
They will have two minutes to answer a multiple choice question by cutting the corresponding wire on their bomb. Snipping the correct cable will disarm it and unlock the letter, while the charge will detonate if the housemate gives an incorrect answer or fails to make a decision in time.
Earlier this week, the group won luxury food rewards after Harry Blake passed a 'Posh Test' and Aden Theobald triumphed in Deal Or No Deal parody 'Reveal The Meal'.
Theobald yesterday became the fifth person to be evicted from the house after losing a public vote to Anton Murphy, Jay McKray, Faye Palmer and Aaron Allard-Morgan.
Watch Aden play 'Reveal The Meal' below: