Reese Witherspoon's character in the movie adaptation of the classic William Makepeace Thackeray novel "Vanity Fair" just keeps getting bigger and bigger. And so does she.

The "Legally Blonde" star, here playing feisty London society girl Becky Sharp, is five months pregnant -- and "Vanity" director Mira Nair is kindly accommodating that fact, reports Reuters.

"We've had a couple of scenes where my stomach was peeking out a bit, but we've found solutions," says Witherspoon, 27 (and one of PEOPLE's 50 Most Beautiful People).

She says she hid her stomach by wearing voluminous period dresses -- the story is set in the 1820's -- and standing behind strategically placed pieces of furniture.

Of the story (which, with Miriam Hopkins, was made in 1935 as "Becky Sharp" and is credited as being Hollywood's first movie in color), Witherspoon says: "It's like nothing you'd expect from an English period film. There's a lot of sensuality, and things which would normally be seen as rather forward."

"Vanity Fair," which still has two more months of filming to go, won't be released until next year. Meanwhile, Witherspoon's "Legally Blonde II: Red, White and Blonde" is due July 2.

"I'm having a great time playing Becky," Witherspoon gushes. "She's a world away from ("Blonde"'s) Elle Woods and for me it's a great departure. It was a natural decision for me to get as far away from American pop culture as I could."

And how about a "Legally Blonde 3"?

"The producer thought it would very funny to have Elle in London, having to go up to the bar with all the barristers," Witherspoon says. "Europe is the next big world to conquer. Elle's conquered America. It's time to conquer the globe."