The cat, which is in recognisable shape and still has its claws and teeth, may have been placed in the walls of the house in Devon, to ward off evil spirits.
Richard Parson, a funeral director, who owns the house in Ugborough, near Plymouth, said: “The builders were stripping one of the bathrooms upstairs and this little fellow came to light.
He added: “Apparently 400 years ago people put cats behind walls to ward off witches. It clearly works as, since we have lived in the village, we have not seen sight or sound of any witches.”
Mr Parson said neighbours have told him the cat was previously found behind the wall 20 years ago, but was put back by another resident.