At least one scene in one episode of the BBC genealogy show Who Do You Think You Are? was staged. The featured celebrity, Carol Vorderman, was unaware of the manipulation.
Vorderman wanted to know where a photo of her great-grandfather was taken and was shown asking passers-by in Prestatyn for help.
Finally, shop assistant Dawn Farrell identified it as Bodnant Gardens in the Conwy Valley.
But Dawn revealed: "A man told me Carol was going to come into the shop with a photo and ask me about it. He said, 'She is going to show you a photo - could you tell her it is Bodnant?' [Link]