Actors who were replaced
The show: "Charmed"
The original actor: Shannen Doherty played Prue Halliwell, the eldest of three sisters who discover they have supernatural powers.
The replacement: This actress's character was introduced as the long-lost Halliwell half-sister in the fourth season, while Doherty's character was killed off
The show: "The Jeffersons"
The original actor: Mike Evans originated the role of Lionel Jefferson on the hit show "All in the Family" and continued playing the level-headed son of George Jefferson in the spinoff "The Jeffersons."
The replacement: Evans left "The Jeffersons" and was replaced by this actor.After four years, Evans returned to the show, but the character of Lionel Jefferson was less important and eventually written out of the series.
The show: "Cagney & Lacey"
The original actor: Meg Foster starred in the TV series "Cagney & Lacey" as Detective Christine Cagney, a role originated in a TV movie by this "M*A*S*H" star.
The replacement: After six episodes, Foster was replaced by this actress, and with the casting change, producers changed the character's back story to appeal to more viewers.
The movies: "Transformers," "Transformers: Revenge of the Fallen," "Transformers: Dark of the Moon"
The original actor: Megan Fox's breakout role was as Mikaela Banes in the 2007 film "Transformers" and its sequel, which made her a fixture in men's magazines.
The replacement: Fox was set to reprise her role as Shia LaBeouf's love interest in the third "Transformers movie," but she was replaced by this Victoria's Secret model.
The show: "Spin City"
The original actor: Michael J. Fox played spin-master and Deputy Mayor Mike Flaherty in this sitcom about New York City politics under Mayor Randall Wilson.
The replacement: When Fox left the show, the series left New York for Los Angeles, and this controversial actor came aboard as the new deputy mayor.
The show: "Dallas"
The original actor: Audiences loved Barbara Bel Geddes as the Ewing family matriarch Miss Ellie Ewing on the prime-time soap opera "Dallas."
The replacement: When Bel Geddes left the show for one season, audiences were disappointed with the quiet, ladylike portrayal of Miss Ellie by another famous sitcom actress and beauty queen
The show: "Roseanne"
The original actor: Alicia Goranson played Becky Connor, the eldest daughter of the working-class Connor family led by matriarch Roseanne.
The replacement: This actress, who went on to star in a hospital sitcom, took over the role of Becky when Goranson left the show.
The show: "The Hogan Family"
The original actor: Valerie Harper starred for two seasons in this show about a busy working mom juggling her career and three children.
The replacement: This actress stepped into the lead role as an aunt and surrogate mom. The show was retitled "Valerie's Family: The Hogans" and later "The Hogan Family."
The movies: "Harry Potter" series
The original actor: Irish actor Richard Harris originated the role of Professor Albus Dumbledore in the first two "Harry Potter" films.
The replacement: Audiences eagerly accepted another well-respected British actor in the role as the headmaster of Hogwarts for the remainder of the films.
The show: "Doctor Who"
The original actor: William Hartnell was the first actor to play the eccentric, time-traveling scientist from a distant planet.
The replacement: After Hartnell left, the show's writers gave the doctor this ability, opening up the ability for multiple actors to take on the role. Some episodes featured more than one Doctor Who at a time.
The movies: "Batman Begins," "The Dark Knight"
The original actor: Katie Holmes received a Razzie Award when she played District Attorney Rachel Dawes opposite Christian Bale in "Batman Begins."
The replacement: This actress was known mostly for indie film success before taking on the Rachel Dawes role in "The Dark Knight."
The movies: "Iron Man," "Iron Man 2"
The original actor: Terrence Howard took on the role of Marvel superhero James "Rhodey" Rhodes in the Iron Man movie starring Robert Downey Jr.
The replacement: In the sequel, this actor took over the role as Iron Man's sometime friend and sidekick, much to Howard's surprise.
The show: "The Fresh Prince of Bel Air"
The original actor: Janet Hubert played Will Smith's "Aunt Viv" in the actor's breakout sitcom about a streetwise youth who moves in with his aristocratic aunt and uncle in Bel Air.
The replacement: Hubert was replaced by this actress after three years
The show: "Star Trek"
The original actor: Jeffrey Hunter took the role of Captain Christopher Pike in the original "Star Trek" pilot.
The replacement: This actor's career took off when he replaced Hunter as a spaceship captain, James T. Kirk.
The show: "Eight Is Enough"
The original actor: Diana Hyland played Joan Bradford, the wife of family patriarch Tom Bradford.Hyland was in four episodes.
The replacement: There was no matriarch in the remainder of the first season of "Eight Is Enough." In the second season, the writers had Tom Bradford meet and marry this actress.
The show: "That '70s Show"
The original actor: Lisa Robin Kelly is best known for her role as Laurie Forman, the manipulating older sister of the main character, Eric Foreman,a teenager living in suburban Wisconsin in the 1970s.
The replacement: In the show's final season, this actress took on the role of Laurie.
The movie: "The Twilight Saga: New Moon"
The original actor: Rachelle Lefevre's breakout role was as villainous vampire Victoria in the first "Twilight" movie.
The replacement: The daughter of a director took over the role of Victoria for the final three movies in the saga.
The show: "Babylon 5"
The original actor: Michael O'Hare took on the lead role of Commander Jeffrey Sinclair in the TV series "Babylon 5."
The replacement: This actor took command of the station as Commander John Sheridan in Seasons 2 through 5 of "Babylon 5."
The show: "Family Matters"
The original actor: JoMarie Payton played Harriette Winslow in this show about a Chicago policeman, his family and their annoying neighbor. "Family Matters" was actually a spinoff from Payton's role as an elevator operator in the sitcom "Perfect Strangers."
The replacement: Payton left the series with just seven episodes to tape and was replaced by this actress.
The show: "Chico & the Man"
The original actor: Comedian and actor Freddie Prinze starred as Chico Rodriguez in the instant hit "Chico & the Man." .
The replacement: Producers almost cancelled the show after Prinze's untimely death, but instead wrote in a new character, 12-year-old Raul, played by this child actor.
The show: "8 Simple Rules for Dating My Teenage Daughter"
The original actor: John Ritter was the lead actor in this sitcom loosely based on a book of the same name..
The replacements: Without Ritter, the family's matriarch Katey Sagal ran the household for a few episodes, but soon got help from an Oscar nominee and this comic actor.
The show: "M*A*S*H"
The original actor: Wayne Rogers is best known for playing Trapper John McIntyre in the TV show M*A*S*H, which took place in a mobile-hospital unit during the Korean War.
The replacement: When Rogers didn't return to the show,this actor moved on to the set as B.J. Hunnicutt, who acted as a straight man to Alan Alda's Hawkeye character.
The show: "Two and a Half Men"
The original actor: Charlie Sheen earned a major paycheck playing self-centered and hedonistic jingle writer Charlie Harper.
The replacement: After much controversy, this actor is joining the show and is now the highest-paid actor on television
The show: "Three's Company"
The original actor: Suzanne Somers starred as the clueless Chrissy Snow in this show about three roommates in Santa Monica, Calif.
The replacements: Somers literally phoned it in during her last season on the show by taping a one-minute "phone call from home" that was supposed to end each episode. When she left, Chrissy's cousin Cindy Snow, played by this actress, took her spot. Later, another actress moved in, playing Teri Alden.
The show: "Bewitched"
The original actor: Dick York played Darrin Stephens, the seemingly oblivious husband of a beautiful, nose-twitching witch named Samantha, played by Elizabeth Montgomery.
The replacement: When this actor arrived to play Darrin, audiences were so jarred by the swap, the phenomenon of replacing actors with no on-screen explanation got a nickname
