Good Behavior
Credit: Vincent Peters

Get ready for a brand new Michelle Dockery. Her new TV series, Good Behavior, premieres tonight on TNT and you'll see a completely different side of her in this role. She stars as Letty Raines, a petty thief who's fresh out of prison and constantly making one bad decision after another. When she overhears a hit man being hired to kill a man's wife, she decides her only course of action is to interfere. From there, her life majorly changes—and not necessarily in a good way.

While we love seeing Dockery in a new light, it's her kick-ass wardrobe in the series that truly stands out, thanks to the show's costume designer Alonzo Wilson. We chatted with Wilson who gave us the scoop on what to expect sartorially in Good Behavior's first season. As for being conscious of her famous Downton Abbey look? "We definitely were aware and made strides and efforts to create a look that was definitely not anywhere near that," Wilson tells InStyle. "Michelle mentioned it once early on, too, and I already didn't have any intention of making anything similar at all, but I did have to be aware of things that had the same style. We really did work hard on that."

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Credit: Brownie Harris

Alonzo tells us that it's important to note the differences in her regular wardrobe versus her con artist wardrobe. "We really wanted the character to have depth ... so we always made sure that the audience knew when she was Letty and when she was someone else," Wilson explains of her two looks. "When she's dressed as Letty, she doesn't seem to make the effort as to when she's playing a role. It's a struggle between who is she and who she'd like to be. When she dresses up, all of her clothes are a fantasy for a better life that she hasn't achieved yet. When the game is on, she will go to the extent of anything—stealing or whatever it is—to do what she needs to do."

Wilson also decided to use high-end items off the rack as opposed to creating couture items himself. "Overall the costumes were character- and story-driven, but keeping in mind that Letty has an expensive taste," he says. "That expensive taste led us to a more stylized and more fashion-forward look for the show. I wanted her to steal things that were current, so the audience would see it and say, 'I'd love to get that,' and then they could actually get it. It made sense that she would steal something that was ready-to-wear as opposed to anything couture that we made. It allows the show to present something to the audience that is attainable."

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Credit: Brownie Harris

Dockery's character is multi-layered and struggles with her current situation, so in the first episode, she turns to what she knows best: stealing pretty things that make her feel better about herself. Of course, since she's in "con artist"-mode, she has to look good while doing it. "With this first look [pictured above], we just wanted to set the tone that anything can happen on this show," Wilson says of Letty's velvet, plunge-neck jumpsuit. "I wanted to find something high-end that worked well for her trying to pretend she actually fits in this world, so that no one would question she's in that hotel. We could have put her in St. John knits and made her look like an aristocratic woman but we wanted her to be sexy. Sexy, daring, hot—all those things worked for her."

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Credit: Brownie Harris

Later in episode one, she goes for a different look to faux-charm the hit man, Javier (played by Juan Diego Botto). She wears a white silk dress with yellow and red designs on it (pictured above). "She's a woman that's trying to do something good and she thinks she's really going to help someone, so I thought we'd make it angelic and went for white," Wilson explains. "The yellow in the dress symbolizes caution for what she's about to do. So we have the fallen angel, flowy, choir robe sleeves, then the yellow is added in, and then the red is added to symbolize injury and bloodshed. On the outside it's really sexy, but deep down the layers have a little more to it."

To see more of Michelle Dockery's killer looks on show, you'll have to tune in tonight for the series premiere.

Good Behavior airs Tuesdays at 9 p.m. ET on TNT.