It's many a girl's fashion dream to raid the closet of every female character on "Mad Men," arguably the most stylish show on television.

And while that's not exactly realistic, we can at least live vicariously through the woman who gets to do it every day: Janie Bryant, the head costume designer on the AMC series, who took home the Costume Designers Guild Award for best period/fantasy TV series earlier this year.

In this exclusive video clip, Bryant, whose designs for "Mad Men" have become one of the most popular characters on the widely influential Emmy- and Golden Globe-winning show, gives a behind-the-scenes glimpse of the costume truck packed with '60s-era gems and talks season 4 fashion (which we'll get to see for ourselves on the July 25 premiere).

"[For] our principal cast, we are adding to their closets, but some of their pieces are still the same. I have new costumes for [Peggy's] accomplishments, for her growth in the company, for changes that are going on for her emotionally," Bryant reveals of fan favorite Peggy Olson, played by Elisabeth Moss. "She has really come into her own. I have reflected that in her costume design."

As for housewife Betty Draper, played by January Jones, expect more of the same classically chic clothing, with a bit of a twist.

"I always think of Betty's style as the idea of perfection. One of my inspirations would definitely be Jackie O," Bryant says while running her hand over Betty's sorbet-hued wardrobe. "Her palette has definitely maintained. She looks beautiful in the lavenders and the blues and the winter whites. There has been a shift in her world and her silhouette has shifted as well."

Overall, says Bryant, in season 4, "we get to see characters not so done up. [It's] a more mod lifestyle, youth culture... There will be more memorable costumes, more glitz, and then there's going to be moments of not-so-glitzy. It's all amazing. Just wait."

We're certainly trying!

Check out the video clip above to hear what lead character Don Draper will be wearing this season and see for the first time what bombshell secretary Joan Harris, played by the voluptuous Christina Hendricks, wears under her curve-hugging ensembles.

In related news, check out what the sexy Hendricks wore to her wedding.