The Little Britain comedian has joined the show to replace Sandi Toksvig as the programme’s co-host alongside Noel Fielding.
He can also be seen making one of the bakers laugh as he is told he is not meant to eat one of the elaborate cake decorations.
He replies: “I know that now!”
The clip opens with Fielding greeting the new batch of contestants, saying: “Hello bakers, welcome to the tent.”
He also tells one: “They can’t contain you, you’re a maverick.”
Judge Prue Leith can be seen tucking into some cake and saying: “I’m struggling not to eat a bit more,” while fellow judge Paul Hollywood delivers the crushing verdict: “That’s bone dry.”
A sculptor, a pantomime producer and a university student are among the 12 amateur bakers taking part in this year’s contest.
Among the hopefuls is Marc, a 51-year-old bronze resin sculptor who lives in Cornwall, who began baking after he lost his leg in a motorbike accident in 2016.
He started making bread as a form of therapy and later progressed to baking cakes and pastries.
Student Peter, 20, who was born in Edinburgh, was inspired by Bake Off to start cooking for himself.
The accounting and finance student, who has also represented his country at badminton, has been baking since he was 12 and has seen every series of the programme.
Pantomime producer Lottie, 31, from West Sussex, has labelled herself a “perpetually frustrated perfectionist” and has had a fascination with cooking since childhood.
Self-taught baker Makbul, 51, initially began cooking at home as a way of supporting his mother.
The accountant, who lives in Greater Manchester, also does beekeeping in his spare time and produces his own honey, which he uses in his bakes.
Other contestants include security guard Dave, accountant Hermine, digital manager Laura, and Linda, who is a retirement living team leader.
Diagnostic radiographer Loriea, project manager Mark, music teacher Rowan and pharmacy dispenser Sura are also taking part in the competition.
The new series will begin on Channel 4 on September 22 at 8pm.
