I saw this movie probably 25 years ago or so, and it was old then. Although I seem to remember it being a Twilight Zone movie, I have started second guessing myself as I can’t find any record of it… I remember it as a full length movie with the Twilight Zone theme, but older than most Twilight Zone episodes.
It was a black and white movie, and the main character (man) was a guest at a manor house or castle I think. He went out to a beach (lake or sea?), where suddenly a woman emerges from the the deep water and walks up on the beach.
I don’t remember much else apart from there being a portrait of the woman inside the manor house, and that at the end it turns out the woman has been dead for a long time, and she ages very quickly in front of the man, her skin and muscles start melting away and she turns into a skeleton (and dust?).
Ringing a bell, anyone? I would love to see it again!