This week's heats continue with the four remaining celebrities facing two more culinary challenges as they battle for a place in the semi-finals. The pairs challenge returns in tonight's first round, as the four celebrities are split into two teams of two, in a test of teamwork and communication. Each team is tasked with cooking the same dish. Both plates must be identical in both appearance and flavour, but there is a catch: between each pair there is a wall. The only way for the celebrities to successfully produce identical plates is by communicating through the wall. The celebrities are then sent out on their first mass catering challenge. Remaining in their teams they will have to make lunch for over 100 members of staff at London Zoo.