Julia Stiles, Kirsten Dunst Squeeze Into Girdles

Actresses appearing with Julia Roberts in upcoming 'Mona Lisa Smile.'

Julia Stiles is stoked to be making “Mona Lisa Smile” with Julia Roberts and Kirsten Dunst, but there’s just one problem.

“We have to wear girdles,” Stiles complained Tuesday night at the premiere of her latest flick, “A Guy Thing.” “And I’m not a big fan of the girdle. So I’ll be glad to be able to take that off.”

Currently nearing completion, “Mona Lisa Smile” has been compared to “Dead Poets Society.” Roberts plays a forward-thinking Berkeley grad in the 1950s who takes a teaching job at the all-women Wellesley College near Boston. The movie also stars Topher Grace (TV’s “That ’70s Show”), Marcia Gay Harden (“Meet Joe Black”), Ginnifer Goodwin (TV’s “Ed”) and Maggie Gyllenhaal, who’s up for a Golden Globe for her performance in the edgy comedy “Secretary.”

“It’s quite a cast,” Stiles said. “It’s been great. I’m excited. I think it’s going to be a really good movie. It’s been a lot of fun.”

As soon as “Mona Lisa Smile” is completed, the “Save the Last Dance” star will enjoy somewhat of a vacation from the biz. “I’m going to school for another semester. And then I’ll probably be working after that. But I’m not quite sure if I want to do a play or a movie.”

Directed by Mike Newell (“Four Weddings and a Funeral”), “Mona Lisa Smile” is scheduled to hit theaters in November.