Big Love
Remember Teenie from Big Love? Apparently, producers were hoping a red wig would trick fans into thinking Jolean Wejbe was not replaced with Bella Thorne. "When I met with producers on the role," said Thorne, "they told me to just make the character my own and not to try and match the other actress," Easier said than done, Bella...
Monk
Trudy Monk was once played by the actress Stellina Rusich, but she only acted on the show for about two seasons before being recast. She was then replaced by Melora Hardin. You might recognize Melora for her much bigger and funnier role as Jan on The Office.