With the seventh and final season of Mad Men off to a great start, seeing how much Don, Joan, Peggy and the gang have changed over the years is more obvious than ever. One of the most dramatic transformations of all is that of Trudy Campbell, played by the talented Alison Brie, who goes from being head-over-heels in love with her husband Pete Campbell, to kicking him out of their family home in season 6. We caught up with the actress, currently starring alongside Adam Scott in a series of hilarious videos for Smirnoff, to find out what it was like developing Trudy as a character, and how she grew from year to year.

“It’s really interesting working on a TV show like this where everything that happens to the character is a constant surprise,” Brie tells InStyle.com exclusively. “I think Trudy started out seeming very superficial and driven by money and appearances. We definitely saw real growth as she struggles with trying to conceive and start a family, which makes you realize that she has more at stake in this life, and has deeper wants and needs than it appeared.”

Trudy later gives birth to her daughter and moves with Pete out of the city to Westchester, and her defining moment came at the end of season 6, when Trudy demands Pete to leave upon discovering he had cheated with a woman from their neighborhood. “I always got the sense that she knew what he was up to most of the time and was willing to look the other way, so it was nice to see her stop putting up with it,” Brie adds. “She found that strength that had always been there, but it was a quiet strength. To see her finally voice it and become this total badass — it was such a good reveal, and it’s a nice confirmation for everyone to know that she’s a lot smarter than she seemed at times.” Amen to that!

No word yet on if Trudy will make a return for the final season (fingers crossed!), but we think her story isn’t quite over. (And any excuse to see her amazing ’60s-era wardrobe is as good as any for us.) “Trudy is very fashion-forward, which I love about her,” says Brie, who notes that a few of her favorite pieces were from the third season. The most-notable for Brie?  Her look in the episode The Grown Ups, in which the assassination of John F. Kennedy became an integral part of the plot. “Trudy and Pete were leaving for the wedding of Roger Sterling’s daughter, but decide not to go once they hear the news about JFK. Before that happens, she comes out in this amazing blue dress, and it could not have been tighter!” she says. “It was a little hard to breathe, but every time I see pictures of it, I’m always like, ‘That was such a killer dress!’ It’s immediately what I think of when I remember my all-time favorite Trudy outfits.” Tune in to a new episode of Mad Men Sunday at 10 PM EST on AMC, and click through our gallery to check out the best looks from season 7 so far!