Darrin Stephens - Bewitched

Perhaps the biggest character replacement in TV history, Dick York (left) left the show in 1969 because he suffered from back problems and was unable to film full-time. When the show replaced York with Dick Sargent (right), the ratings took a dive and never recovered. 

Image: Sony Pictures Television

Becky Conner - Roseanne

This might be the most confusing character replacement of all time. When Lecy Goranson (left) decided to attend Vassar College, she was replaced by Sarah Chalke (right). In the eighth season, Goranson returned and alternated episodes with Chalke. But when Roseanne was picked up for a ninth season, Chalke resumed the role of Becky Conner full-time. 

Image: SFM Entertainment

Chris Partridge - The Partridge Family

Brian Forster (right) replaced Jeremy Gelbwaks (left) after the first season when his family moved away from Los Angeles. But his departure was a welcome one, with David Cassidy saying Gelbwaks "had a personality conflict with every person in the cast and the producers." That's a lot of drama for such a small kid!

Image: Sony Pictures Television

Alice Kramden - The Honeymooners

Pert Kelton (left) originally portrayed Alice Kramden in The Honeymooners skits. However, she was replaced by Audrey Meadows (right) after being blacklisted from Hollywood. When Jackie Gleason revived the characters in color in the late 1960s, Sheila MacRae stepped into the role.

Image: Wikipedia

Leonard Unger - The Odd Couple

Before they were teen heartthrobs, Willie Aames (left) and Leif Garrett (right) shared the role of Leonard Unger on The Odd Couple. 

Miss Ellie Ewing - Dallas

Barbara Bel Geddes (left) originated the role of Miss Ellie Ewing in 1978 and played her until her departure in 1984. That's when veteran actress Donna Reed (right) took over, but only for one year. When Bel Geddes returned, Reed sued for breach of contract and settled for seven figures. 

Image: Warner Brothers Television

Gladys Kravitz - Bewitched

The popular Alice Pearson (left) won an Emmy for her portrayal of Gladys Kravitz. Unfortunately, she died of ovarion cancer during the second season. Producers decided to replace her with Sandra Gould (right), who held her own for the rest of the series.

Image: Sony Pictures Television

Marilyn Munster - The Munsters

The details are a little murky as to why the show replaced Beverly Owen (left) with Pat Priest (right) after 14 episodes. But if you never noticed the difference, you're not alone. Both actresses looked so similar, many viewers didn't notice the change. 

Image: NBCUniversal

Catwoman - Batman

Despite only lasting three seasons, Batman had two different (and distinct) cat-women. Julie Newmar (left) portrayed the villain for the first two seasons, but was replaced by Eartha Kitt (right) in season three when she was unavailable to film. 

Lionel Jefferson - The Jeffersons

Just like Becky Conners on Roseanne, two actors took turns portraying this role. Mike Evans (left) originated the character of Lionel Jefferson, but was replaced by Damon Evans (right, no relation) during the second season. Damon stayed until the forth season, when Mike took over the recurring role.

Image: Sony Pictures Television

Jenna Wade - Dallas

Jenna Wade appeared sporadically on the first few seasons of Dallas, first played by Morgan Fairchild (left) and then by Francine Tacker. It wasn't until 1983 that the role became more prominent, thanks to Priscilla Presley (right). 

Image: Warner Brothers Television