Reese Witherspoon was a natural as that delightfully perky California girl in Legally Blonde. But she goes, like, totally against type in her newest film, The Importance of Being Earnest (opening May 24). Mastering a British accent for this Oscar Wilde adaptation — which co-stars bonafide Brits Rupert Everett and Judi Dench — wasn't easy.

"It took me six weeks to learn that accent," Witherspoon tells TV Guide Online. "I was working and working like a dog on it for three hours a day before I even started [filming].

"The only thing that was a little unfortunate was that I had to go back and replace all the dialogue in the postproduction process," she reveals. "And I was in the middle of doing a movie where I had a Southern accent. So I had one day — basically 19 hours — to replace 85 percent of my dialogue that I didn't remember. I didn't remember that English accent at all. So, it was sort of a crap shoot."

Not that there was anything wrong with her performance the first go-round — the do-over was necessitated by technical difficulties. "We shot next to an airfield," the 26-year-old explains. "It was beautiful, that estate. It was really nice, but... there were planes [drowning out] everybody's dialogue."

Witherspoon had another obstacle to overcome before she even arrived on the Earnest set: spousal envy. Her adorable hubby Ryan Phillippe had managed to master a Scottish accent for Gosford Park in record time. "[He] studied for three days," she marvels. "And he got it perfectly.

"It took me six weeks to prepare," she gripes, "and he kept looking at me [and saying], 'Why are you spending so much time preparing? It's so easy.' I'm like, 'No, it's really hard.' Not all of us can hear [an accent] like that. So I was jealous!"