Originally, Carol Burnett was supposed to play Thelma Harper instead of Vicki Lawrence
Burnett chose the role of Eunice instead.
One of the wonderful things about The Carol Burnett Show is that, while Burnett herself is spearheading the effort, it still feels like an ensemble production. Sure, Burnett's name is in the title, and when you remember the series, you may even consider her the star if you were pressed. But Burnett herself was incredibly modest. More than that, she was a team player, eager to see her fellow actors succeed and thrive, and just as delighted to laugh at them along with the audience.
A great example of this appeared in an interview with Vicki Lawrence in the St. Louis Post-Dispatch. In it, Lawrence revealed that originally, the popular part of Mama had been written for Burnett herself, but she turned it down.
The character may have originated on The Carol Burnett Show in a series of gut-busting sketches, but it quickly took on a life of its own, reaching greater heights as it was developed into a television series. In fact, at the time of the interview, Lawrence was busy promoting her production: Vicki Lawrence and Mama: A Two-Woman Show. In it, Lawrence performs as herself and Thelma Harper.
In the interview, Lawrence explained Burnett's decision to play the character of daughter Eunice instead of Mama herself. She said, "She thought Eunice was the part that spoke to her." Because of this, the role was later offered to Lawrence instead, who was still grateful for the part after all these years. She stated, "So Mama was another gift from Carol."
Lawrence herself felt that Mama spoke to her so deeply that she once called the character her "alter-ego" in an interview with the Arizona Daily Star. The actor revealed that Thelma often said "all the things that I would love to say but would never have the nerve to say because they're politically incorrect or wrong." Even if you aren't a Mama, Lawrence expressed, you know a Mama. She stated, "Everybody had [someone like Mama] in their family."