We've seen it in a few movies where a main character is replaced by a different character in sequels, though it's more uncommon to see the same character re-cast with a new actor - but sometimes it happens. Just look at the Thor films: in 2011, Josh Dallas (Once Upon A Time) portrayed the character, Fandral, but in the followup Thor 2: The Dark World, Zachary Levi (Heroes Reborn, Chuck) played Fandral. Other character re-casts include: Batman, The Incredible Hulk, Freddy Krueger and a few others; but the sequel effect is bound to happen, especially when it takes several years to develop films for production. So it's interesting to watch a television show replace actors; sometimes between seasons and other times between episodes within the same season.
There are countless shows that are fairly unknown that replace actors to try and dig up fan interest, but when a major show replaces an actor, it's kind-of a big deal. Here are a few characters that you may not have noticed were re-cast.
1. Babylon 5 - Anna Sheridan
Portrayed by: Beth Toussaint & Melissa Gilbert
Babylon 5 was a Sci-Fi show that aired in the mid/late 90's for 5 seasons, and was incredibly popular at the time. It still is popular in many circles, and is considered one of the better sci-fi series ever created. In the second season we met John Sheridan's wife, portrayed by Beth Toussaint, as a crew member on the Icarus, the Interplanetary Expedition ship, that John captains. She comes in contact with an alien race and is changed by the aliens. Believed to be dead, Anna returns in season three, now portrayed by Melissa Gilbert, in order to lure John back to the alien's home planet.
2 & 3. Being Human - Annie Sawyer & John Mitchell
John Mitchell portrayed by: Guy Flanagan & Aidan Turner
Annie Sawyer portrayed by: Andrea Riseborough & Lenora Crichlow
Being Human, the original BBC show, recast two of the three main characters after the pilot aired. Initially Annie was cast as Andrea Riseborough and Mitchell as Guy Flanagan, yet by the second episode they were replaced by Lenora and Aiden respectively. Recasting after a pilot isn't unheard of, but replacing two characters out of three is a little excessive in comparison to a single character that doesn't play a main role.
4. The Fresh Prince of Bel-Air - Vivian Banks
Portrayed by: Janet Hubert-Whitten (90-93) & Daphne Maxwell Reid (93-96)
"Now, this is a story all about how my life got flipped-turned upside down. And I'd like to take a minute, just sit right there I'll tell you how I became the prince of a town called Bel Air..." - You're all probably singing the theme in your head now, and that's part of what we loved about the show along with the phenomenal cast. We were first introduced to Vivian Banks, Will's aunt, portrayed by Janet Hubert-Whitten for the first three seasons of the show. But when she violated her contract by becoming pregnant, she was fired from the show and replaced by Daphne Reid for the remaining seasons.
5. Game of Thrones - Daario Naharis
Portrayed by: Ed Skrein & Michiel Huisman
Season 3 of the acclaimed HBO show, Game of Thrones, introduced us to as a member of the Second Sons who refuses to obey his superiors when tasked with assassinating Daenerys Targaryen. He, being third in command of the mercenaries slays his captain and 2nd in command (in self-defense after refusing to kill Daenerys) and in turn takes command of the men below. He then swears loyalty to Daenerys, who he has become smitten with. Through the three episodes in season 3, Ed Skrein brought Daario to life, but was replaced at the beginning of season 4 by Michiel Huisman.
6. Monk - Trudy
Portrayed by: Stellina Rusich & Melora Hardin
This re-cast was probably more difficult to notice as she is actually dead at the beginning of the show. Through the first two seasons of Monk, Stellina Rusich was used in flashbacks and in photographs as Trudy Monk. Yet in the third season, it was necessary to re-cast the character and after much searching, the executive team and Tony Shaloub (who portrayed Monk himself) settled on Melora Hardin to replace Stellina
7. My Wife and Kids - Claire
Portrayed by: Jazz Raycole & Jennifer Freeman
Sometimes there are times when a character needs to change to progress the show, and that's what happened in the Damon Wayans comedy, My Wife and Kids. In the show, Damon's character Michael and his wife have three children, the middle child being a girl named Claire, portrayed by Jazz Raycole. In season 1 Clair is a sweet, pre-teen girl who goes through the basic pains of being a pre-teen girl (first crush, first bra, etc. etc.) but in season 2, Claire is rapidly aged by 3 years and replaced by Jennifer Freeman who finishes out the remaining 4 seasons of the show.
8. That 70's Show - Laurie Forman
Portrayed by: Lisa Robin Kelly & Christina Moore
The show that spawned careers for several young actors including Wilmer Valderrama (Awake, Minority Report), Laura Prepon (Orange Is the New Black), Ashton Kutcher (The Ranch, Two and a Half Men) and Topher Grace (Predators, Spider-Man 3). The show revolved around the collection of friends as they dealt with various social and personal issues, Eric Forman, portrayed by Topher Grace had an older sister, Laurie, who was initially portrayed by Lisa Robin Kelly for the majority of the first 5 seasons, but was replaced in the 6th season by Christina Moore.