The Suits superfan makes her debut as power attorney Samantha Wheeler in the eighth season of USA Network's long-running legal drama (the first without series stars Patrick J. Adams and Meghan Markle), and her introduction to the world led by hotshot lawyer Harvey Specter (Gabriel Macht) is about to make major waves within the halls of Zane Specter Litt.
"Samantha is really fierce," Heigl told ET's Keltie Knight during a June set visit in Toronto, Ontario. "I keep hashtagging her #girlwithgumption 'cause she is. She just doesn't take any sh*t and she is not intimidated or afraid of any of these guys, and she has this attitude of 'Well, if this doesn't work, something else will. I always come up with something that will work.' She doesn't let anything [get to] her and she's a little crafty. She's a little underhanded."
The 39-year-old actress characterizes Sam as a "giant" manipulator, but in the best way possible, as she sometimes twists the truth to get the edge for a client or the firm. "She does that to see who's gonna bite what and where, and if she can use different stories to manipulate different people," Heigl explained. "She's really clever."
Plus, Sam's chic designer wardrobe may give firm COO Donna Paulsen (Sarah Rafferty) a run for her money. Heigl shared that she had input when it came to her character's outfits. "At one point, the producers were wanting a more lawyer look and I went, 'Are you nuts? No, I want to wear the Dior,'" she shared. "It's been really exciting because we find that middle ground of her being professional but still getting to wear the glory."
"There's something about the idea of a woman walking into a corporate room or a corporate lawyer's office with all these men and standing out in something beautiful and not trying to fit in by wearing a dark suit. No, make a statement, distract and confuse, and that's part of her strategy," Heigl added.
Heigl's casting became official in January, soon after Adams and Markle's departures after the seventh season were announced. Heigl, who won an Emmy in 2007 for Grey's Anatomy and has toplined several dramas (CBS' Doubt and NBC's State of Affairs), expressed some fear over joining a show that's been an established hit -- one she happens to be obsessed with!
"My biggest fear was coming on and ruining my favorite show by being on it," Heigl confessed. "Like, oh my gosh, am I just gonna completely screw this whole thing that I really like already? But it was too exciting to get to play in a world that I have just been in love with for so many years."
Heigl revealed that she "took initiative" in getting herself cast on Suits, sharing that she came aboard the new season by happenstance through a meeting with creator Aaron Korsh about something else.
"I have a couple of my own shows that I'm developing and we wanted to talk to Aaron because I'm such a giant fan of his writing and what he's doing here," she said. "We didn't know there was going to be an eighth season, so I thought he might be available. The course of that conversation was -- he was like, 'I'm gonna be doing another season of Suits,' and I was like, 'Do you need anybody 'cause I'm available!' And so, it kind of happened. I was thinking a guest on an episode here and there, and then it turned into a season arc, which is thrilling and so great."
Like a true Suits fan, Heigl couldn't contain her excitement the first time she stepped onto the law office set where most of the action takes place. "[It] blew my mind," Heigl recalled. "We did a camera test in Louis' office and I was like, I'm in Louis Litt's office."
But relocating to Toronto with her husband, musician Josh Kelley, and three kids -- daughters, Adalaide and Naleigh, and son, Joshua Jr. -- from their home base in Utah has been quite an adventure.
"It's a lot," she admitted. "Gone are the days where you would just pack a suitcase and go and be on location for nine months. It's taken me a really long time to somehow wrap my brain about the fact that they're over, so when you're looking for a place to live, I have to keep in mind, I need these many bedrooms, and I also raise my niece, so she's with us -- there's four kids, my husband and I, and two dogs. It's chaos but we're getting it together and better and down to a science."
Heigl had only lovely things to say about the Canadian city, in which Suits is headquartered, and shared that her children are adapting quickly to their new way of life, often visiting her on set. "They love craft services and they can get bowls and cups of candy -- that's the only reason they come," Heigl said later. "They act like they're excited to see me, they're not. They just want the candy!"
Suits premieres Wednesday, July 18 at 9 p.m. ET/PT on USA Network.