"Betty was the kind of role I'd never played before," Dunst said in production notes for the film. "It was so much fun to play the (expletive). Betty is so uptight, so narrow-minded. She doesn't question anything. And as soon as anyone challenges her, she shuts them right down."
The actress insists her character isn't all bad, though.
"She's mean to people, especially (Roberts' character,) but it's because she's so unhappy," explained Dunst, who gained fame for playing Peter Parker's love interest in the 2002 blockbuster "Spider-Man."
In the film, Roberts plays a 1950s-era art professor who encourages her female students at Wellesley College to think for themselves. Dunst plays one of her more stubborn pupils.