The Good Life (1971)

Ordinary middle-class couple Albert and Jane Miller became bored with their lives and decided to pretend to be the butler and cook for Charles Dutton, the very wealthy head of Dutton Industries, and his family. Only Dutton's teenage son Nick was aware of Albert and Jane's true identities, and he often helped them get out of whatever trouble their secret had caused them. Dutton's busybody sister Grace was constantly trying to undermine the Millers' authority and get them fired.