The former Made in Chelsea star - who is vegan - appeared alongside farmer Mat Carter from Devon, who made headlines when he offered people the opportunity to name and feed their chosen turkeys, before the animals were slaughtered and eaten.
Carter claims he has since received death threats from vegans, who have called him psychotic and a murderer. Graffiti has appeared on the door of his farm shop, and blue paint was sprayed over dead birds. Carter says the media attention has made his sales double.
During the segment, Watson asked Carter: "What do you mean by ethical exactly?"
"Well, been well looked after, slaughtered humanely and looked after in the best way possible," replied Carter.
She then asked: "What is humane slaughter, exactly?"
"Well, in the most stress-free [way] possible," Carter answered, after pausing and appearing uncomfortable.
"What does that entail?" Watson continued.
Carter, still refusing to outline how the birds are killed, said: "Well, it involves killing the turkey. You can't have Christmas dinner without killing the turkey."
Watson asked: "Just out of interest, how do you kill the turkey? I'm just genuinely curious."
"You slit the turkey's throat," Carter admitted.
Watson was then quizzed by show host Philip Schofield on her thoughts on the concept of naming and feeding animals, before eating them.
She revealed that she thought it was 'psychotic' at first, adding: "This is the way that you would treat a pet.
"I disagree with the killing of animals full stop, but in a way it's good, because I want people to be able to make a connection with these animals and make people realize they have souls and they're gentle creatures."