There were four options to choose from; Diet Coke from a can, Diet Coke from a glass bottle, Diet Coke from a plastic bottle - and an off-brand variant.
Next up was trainee reporter Emily Cooper and although she enjoys Diet Coke, she admitted she had 'no idea' which was which.
He then incorrectly guessed that the plastic bottle Diet Coke was the supermarket cola from Sainsbury's, before predicting that the Sainsbury's low sugar beverage was Diet Coke from a glass bottle.
However, she did struggle with distinguishing between Diet Coke and Coke Zero, before saying: 'My favourite is Diet Coke, I drink it all the time, far too much.'.
First up was Emily, who managed to detect original Coke's distinct taste from Pepsi Max.
