Contestants will be asked to cook meringues, tarts, and a tiered cake during the show which will be aired on October 9.
"Next time, we're throwing out the eggs and butter in our first ever vegan week," said host Noel Fielding.
"For the very first time on the show, Vegan Week takes place," says the official synopsis for the episode.
"Judges Prue Leith and Paul Hollywood have set three very different challenges to test the remaining bakers - a savoury pastry Signature, with no butter involved, a Technical with a very unusual ingredient and a spectacular Showstopper that in the heat of the tent threatens to lead to catastrophe.
"Who will keep their cool and win star baker? And who will be meeting their end?"
Speaking about the new series at the show's launch, Paul Hollywood, who hosts GBBO along with Sandi Toksvig, Noel Fielding and Prue Leith, said: "We wanted something different and something to represent what was happening in this country. Veganism is something that seems to be growing. That's why it is in.
"If you are a vegan or you're thinking about it and are just worried about how it is going to change your life, watch it and see. It fascinated me, totally … shocked me as well."
He added that the judges maintained the same strict standards when assessing the bakes, saying: "You can't judge it and say it's okay for vegan, it's got to taste good, period. That’s how we judged it and we were surprised."