It's Christina Applegate like you've never seen her before. The former Married... with Children sexpot is trading tight T-shirts for period garb in her new film, Just Visiting — an English-language remake of the 1993 French pic Les Visiteurs — in which she plays an 11th century princess.

"It was the age of chivalry, when men treated women like ladies," Applegate, 29, tells TV Guide Online. "Now, that sense of chivalry in men has died, and I think we're partly responsible for messing it up. We kept telling the guys, 'We're equal.' Now, they're like, 'Fine. You open the damn door.'"

Applegate says her decade-long stint as Married's IQ-challenged Kelly Bundy gave her the confidence she needed to hold her own in the time-tripping romantic comedy, which opens today. "I wasn't always funny," confesses the actress, who last year headlined the short-lived NBC comedy, Jesse. "I learned how to get laughs from [co-star] Ed O'Neill. I took myself a little too seriously when I first stepped on the set. I was the intense dramatic gal, and Ed helped me find my sense of humor."

And although she played an adolescent boy's ultimate fantasy on the late Fox sitcom, Applegate says she hardly felt sexy parading around in those skimpy outfits. "I was going through that really awkward phase," she remembers. "I felt the way every teenager feels, but my awkward phase and my really bad hair was getting documented every week on TV and in re-runs."

Now, with Applegate's movie career blasting off — upcoming projects include A View from the Top opposite Gwyneth Paltrow and The Sweetest Thing with Cameron Diaz — it's unlikely she'll be heading back to the small screen anytime soon. And that suits her just fine. Laughs the thesp: "Been there, done that, bought the T-shirt."