The Ghost & Mrs. Muir - Season 2 - Eps 23: Curious Cousin
Carolyn's cousin Harriet comes for a visit and somehow jumps to the conclusion that Carolyn and the Captain are an item, not knowing that the Captain has been dead a hundred years.
About The Ghost & Mrs. Muir

Title: The Ghost & Mrs. Muir
First Air Date: 1968-09-21
Last Air Date: 1970-03-13
Status: Ended
Rating: 6.4/10 (from 16 votes)
Language: EN
Seasons: 2
Total Episodes: 50
Network: ABC NBC
Genres: Sci-Fi & Fantasy, Comedy
Production Companies: Unknown
Synopsis
Derived from the 1947 movie with the same name, a house is haunted by a deceased sea captain who wreaks havoc with the new tenants who were not advised of his existence.
Cast

Edward Mulhare
Captain Daniel Gregg

Hope Lange
Carolyn Muir

Charles Nelson Reilly
Claymore Gregg

Reta Shaw