By Samantha Simon
Updated Jan 07, 2016 @ 8:30 pm
Credit: Peter Kramer/NBC

When Shades of Blue premieres tonight (10 p.m. ET), get ready to see a whole new side of Jennifer Lopez. InStyle’s February cover girl may be known for rocking body-hugging outfits that make a statement every time she hits a red carpet, but the star is far from glamorous onscreen in her new NBC series. In addition to executive producing the drama, Lopez plays shady NYPD detective turned FBI informant Harlee Santos, a single mom whose toned-down wardrobe is all about the basics.

From day one, Lopez had a distinct vision for her character. “The whole concept of the clothing was really hers,” the show’s costume designer, Ellen Lutter, told InStyle earlier today. “Jennifer was very interested in going for a baggy, man-tailored look that harkens back to the ‘80s a bit. Nothing really had a true feminine quality to it, and she wears a lot of loose pants, tissue T-shirts, and drapey clothing made of thin and soft fabrics on the show.”

Credit: Peter Kramer/NBC

Don’t mess with Jennifer Lopez—or rather, Harlee Santos, the NYPD detective she plays in this new drama. When the FBI picks up on the single mom’s illegal activity, she has no choice but to turn on her own unit and become the Feds’ secret informant. The series, which is executive produced by Lopez, also stars Ray Liotta as the unit’s lieutenant and Drea De Matteo as a fellow detective. (Jan. 7, 10 p.m. ET on NBC)

Peter Kramer/NBC

One of her character’s main wardrobe staples is just “a simple T-shirt,” according to Lutter. “It can really go far in yanking something down from being too dressed or high-fashion.” And when crafting Harlee’s look, that was Lutter’s main goal. “This woman is in love with her work and she’s also a mother,” she said. “She doesn’t really spend a lot of time putting herself together, but she looks great. She dresses cleanly and classically and it’s put together in an appealing ‘I’m going to roll up my sleeves and get to work’ kind of way.”

That’s why Harlee’s ultimate style is “not so uptight and conservative,” said Lutter, adding that “there isn’t much of a rigidity” in Lopez’s onscreen wardrobe. “Harlee would shop at stores like Zara, Club Monaco, Gap and Forever 21 for her basics.” But while Harlee goes for more casual looks than Lopez does IRL, the star still brings a sexy edge to the role. “Even though she plays a rugged character, there’s a certain sex appeal and darkness to her,” Lutter said. “You still get a definite sense of her body. It’s amazing the sort of silhouettes that she’s able to carry, and the draped, thin fabrics are actually very sexy.”

Credit: Peter Kramer/NBC

Lopez—whose stylist Rob Zangardi helped put together initial fittings for the show—even wears a few tight-fitting outfits reminiscent of her real-life style onscreen. “At one point, she wears a Victoria Beckham skintight dress,” said Lutter. “But even her tighter outfits are a departure from what Jennifer is known for and the looks that you’re used to seeing her wear. I think she did an amazing job transforming from ‘Jennifer Lopez’ into this cop.” Her character may be drawn to simpler fashions, but “there is still a glamour factor” to the show, according to Lutter. “It’s an interesting kind of New York fashion look that’s not flashy, although you’re totally aware of her body and her sex appeal.”

While many of Lopez’s onscreen outfits come from labels like Band of Outsiders, Public School, A.L.C., and Rag & Bone, Lutter also sourced pieces from stores like Club Monaco, Zara, and J. Crew. “The looks are a lot funkier than what you normally see representing what cops wear on television,” said Lutter. “It’s not your typical trim suit.” Lopez’s favorite pieces in her character’s wardrobe? “She loved her Converse sneakers and a Zara trench coat, but there wasn’t anything that she didn’t love. She was very cool with wearing all of the clothes.”

Credit: Peter Kramer/NBC

Lopez even brought a few pieces of her own to the set. “She brought some shoes, like a pair of high-heeled boots from her own line,” said Lutter. “She also brought a Zara jacket that was hers, a pair of Yves Saint Laurent pants, and some of her favorite A.L.C. T-shirts.” While they were filming, Lopez was extremely hands on—and despite her busy schedule, she gave the role her undivided attention. “Jennifer is one of the hardest working people,” said Lutter. “She was completely focused and aware of her character, and as soon as she got to work, she just became Harlee.”

And Lopez’s work ethic was laid-back. “She’s so cool and relaxed, but also in-command and confident,” said Lutter. “Nothing turns into drama, and the fact that she was producing this and in control of things but was also able to let go at the same time was just incredible.” But the best thing about dressing Lopez? “She’s got nerve,” said Lutter. “She’s comfortable in her own skin, and she’s not worried about wearing something baggy.”