Hey, It's That Guy!: Recurring guest Harry McGraw is a lot more recognizable as Law & Order's Lennie Briscoe. Other well-known guest stars who had later roles:
George Takei of Star Trek played a janitor whose collection of celebrity trash helps Jessica.
Leslie Nielsen appeared twice in two consecutive seasons, first as a captain of a cruise ship on which Jessica was a passenger, and then as a treasure-hunting old friend of Jessica.
John Astin from The Addams Family appeared at least twice as the same character.
"The Murder of Sherlock Holmes": One of the thugs who tries to mug Jessica in the alley is none other than a young Andy Garcia!
Name's the Same: "Old Habits Die Hard" has a seemingly-Jerkass boyfriend character named Michael Phelps.
In "Murder at a Discount", George Segal's character is named Dave Navarro.
What Could Have Been: Jean Stapleton, better known asEdith Bunker, was first offered the role of Jessica Fletcher. Stapleton passed - ironically, given that she's on record as being unhappy with her Type Casting as Edith, and this show likely would have rescued her from that fate. In any event, the producers then offered the role to their second choice, Angela Lansbury, who gratefully accepted.