A couple of fun horror facts regarding the movie. Firstly, the skeleton in the coffin was real.
None of the actors except Tim Curry and Richard O'Brian knew there was a corpse in the table. Hence, the distressed look on their faces was real when the tablecloth was removed.
That castle, Oakley Court, is now a hotel - but back in the 1970's during filming, it had no toilets nor heat. Yikes! Those poor actors prancing about in nothing but underwear. They must have been freezing.