TV Shows That Had An Actor/Actress.....

Spartacus - Andy Whitfield.

The Beast - Patrick Swayze
The Clone Wars - Ian Abercrombie

Had no idea Andy Hallett had passed - how sad.

Cheers--Nicholas Colasanto. His bartending job was taken over by Woody Harrelson's character.

Hill Street Blues--Michael Conrad, whose sergeant character was best known for the show's famous line, "Hey! Let's be careful out there."

Night Court--When elderly, chain-smoking Selma Diamond passed away after the first few seasons, her bailiff job was taken over by a character played by Florence Halop. The elderly, raspy-voiced Halop also passed away about a year later. The show decided to go with a younger, presumably healthier actress,
Marsha Warfield, who thankfully survived the rest of the show's run.

The Goldbergs (1949-1957)--when actor Philip Loeb was blacklisted in the 1950s, he was forced off the show, which resulted in his suicide soon after.

Chico and the Man--Freddie Prinze (Sr.), at the height of his success with this show, committed suicide. The producers of the show tried to continue
the series by replacing Prinze with a young boy; viewers lost interest and the show was soon cancelled.

Eight is Enough--Diana Hyland, who played the mother of the Bradford children, died early in the show's run. Betty Buckley was brought in somewhat too quickly as a romantic interest for Dick Van Patten's character and, inevitably, as the stepmother for the children. 

The Waltons--Will Geer, who played Grampa Walton, passed away several seasons into the series. 

Petticoat Junction--Bea Benaderet, the mother of the three girls on the show, became ill during the run of the show and June Lockhart was brought in as a kind of temporary unofficial stepmom to both the girls and a keeper to goofy Uncle Joe. Benaderet later passed away and Lockhart's character stayed on.

My Three Sons--William Frawley played "Bub," the boys' maternal grandfather and housekeeper to the Douglas family. When he died of a sudden heart attack, actor William Demarest was brought on as "Uncle Charlie," a replacement crusty but kind-hearted old curmudgeon (the family was apparently full
of them).

Sesame Street--Will Lee, who played Mr. Harold Hooper, owner of Hooper's Store, was one of the original human characters to appear on the show when it first began its run. When he died in 1982, the producers of the show decided to use his passing as a lesson for its young viewers. The show had the character of Mr. Hooper also die, with the other characters discussing the topic of death in a way that children might understand.

Dick Cavett had a guest die while the show was being taped. The show never aired.

Elisabeth Sladen - played "Sarah Jane Smith" on Doctor Who and The Sarah Jane Adventures. She died from cancer in the middle of the production of Season Five. Without "Sarah Jane Smith", The Sarah Jane Adventures could not continue.

The mom from The Sopranos (Nancy Marchand). They actually had to CGI her for her final episode.

Carol Ann Susi - Big Bang Theory
Donna Reed - Dallas
Phil Hartman - NewsRadio - Murdered by his wife
Rebecca Shaffer - My sister Sam - Murdered by a stalker

Mark Frankel - Kindred: The Embraced - Road accident