It might seem like just another dopey comedy, but Viva Rock Vegas star Kristen Johnston says she really worked hard at showing movie audiences a whole new side of cartoon icon Wilma Flintstone.

The veteran theater actress and star of NBC's 3rd Rock From the Sun says the movie ? a prequel to the popular 1960s TV cartoon The Flintstones ? called for her to present a very different side of the character than the all-knowing matriarch that TV audiences have loved for decades.

"I didn't really look at it as playing the Wilma we know," she tells TV Guide Online. "I thought it was sort of important to make her much more innocent and naive, kind of dorky, insecure. So I didn't really play an icon, actually, I just played this young version of an icon."

Johnston had always considered herself to be more like the Flintstones' somewhat more laid-back neighbor, Betty Rubble. In fact, she initially thought she should try out for the Betty role when she was approached by the Viva Rock Vegas producers.

"But then I read the script and I thought, 'You know, this would be such a cool thing to try to pull off,' " she says. "I'm playing somebody who is so innocent and open-eyed and naive and goofy and earnest, and that's why she's funny. And then she finds her strength. Not to belabor this project ? it is The Flintstones but every episode of the cartoon has some heart to it. I think that we tried to remain true to that."