Kate Winslet on HBO’s ‘Mare of Easttown,’ her ‘Titanic’ accent and funny nickname from Jack Black

In HBO's "Mare of Easttown," Kate Winslet plays a brooding small-town detective named Mare Sheehan, also known as Lady Hawk from her days as a high school basketball star.

Winslet, too, has a long-standing nickname, started by one of her co-stars in 2006 rom-com "The Holiday."

"People don't really call me Kate at work; they call me K-Dub," the Oscar winner tells USA TODAY. "It was started by Jack Black, actually. He was like, 'Hey, K-Dub!' and then it just stuck. I find myself, whenever I sign a work email, I automatically just put K-Dub. And that has been the case for a long time. It's funny, isn't it?"

K-Dub – or rather, Winslet – is back on the small screen in "Easttown" (premiering Sunday, 10 EDT/PDT), her first TV project (and second HBO miniseries) after her Emmy-winning turn in 2011's "Mildred Pierce."

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Like Nicole Kidman's addictive (and high-rated) HBO limited series "The Undoing" last fall, "Easttown" is a twisty, nail-biting whodunit, this time set in rural Pennsylvania. The seven-episode drama begins with the murder of a troubled teen mom (Cailee Spaeny), which could be linked to the long-unsolved case of a missing local girl.

Mare quickly becomes consumed by the investigation, aided by a kindly county detective (Evan Peters) who's new to town. She juggles her work on the case with being a single mom to her teen daughter (Angourie Rice) and keeping a potential suitor (Winslet's "Mildred Pierce" co-star Guy Pearce) at arm's length.

Winslet, 45, says Mare is unlike any woman she's played before: a "remarkable real character" who's equal parts "lovable and loathsome."

"She feels like a person you'd meet on the street," Winslet says. She's "someone who is so stuck in the daily grind of life and just expecting things to be hard each day, not knowing that she can find ways to move beyond what feels insurmountable. And yet she just keeps going, doing things for other people and letting them lean on her."

Mare also lacks vanity. "She eats all those terrible foods – I mean, putting the Cheez Whiz on the cheese ball was a personal touch of my own," she says, laughing. "And I loved it."

"Easttown" was created by screenwriter Brad Ingelsby ("The Way Back"), who was loosely inspired by his own upbringing in Berwyn, Pennsylvania, as well as British crime dramas "Broadchurch" and "Happy Valley."

Aside from the show's central mystery, he was interested in exploring larger themes of generational trauma and mental illness, as Mare wrestles with guilt over the suicide of her addict son, Kevin (Cody Kostro), and wonders how she can prevent her young grandson (Izzy King) from going down a similarly destructive path.

"It's really a story about a woman who has to confront grief," Ingelsby says. "How would this character of Mare carry that grief? That inability to confront the thing that was in her son and her own inability to be the parent she probably could have been? And then having to experience it again with her grandson and wanting the chance to right the wrongs of what happened with her son. I thought that was really compelling."

Winslet has three children from different marriages: Mia, 20, Joe, 17, and Bear, 7. Her maternal instincts made it difficult to shoot flashback scenes between Mare and Kevin, to the point that she frequently found herself crying between takes.

Kevin "became a real person for me," Winslet says. "Even when (Kostro) was on set, I couldn't even look at him or be in the same room as him. I would just have to quietly be somewhere else until we actually had our scene because it would just come tumbling out of me.

"As a mother, your desire in life is to have healthy children who are OK and happy and to not do any wrong by them," she adds. "Mare does (expletive) up. She could have handled things differently and done a lot more. And in our show, we're watching a woman come to the realization that she has all those flaws and faults. So the unbearable guilt she feels every day is something that really affected me enormously."

Winslet, who lives in the U.K., moved her family to the Philadelphia area several weeks before shooting began in fall 2019. She shadowed members of the Easttown and Marple Township police departments and immersed herself in the Delaware County (or "Delco") dialect. Words such as water (pronounced "wooder") and Cheerios ("Churry-oos") were particularly tough to master.

The British actress has done German ("The Reader") and Polish-Armenian-Russian accents ("Steve Jobs") before. But the Delco accent "is up there in the top three hardest dialects I've ever done, for sure," she says. "I had to work on it every single day."

But she still feels she pulled it off better than her American accent in "Titanic," her 1997 blockbuster breakthrough. Winslet told CNN in 2012 that her accent in that movie is "awful" and "I can't listen to it."

"I can hear me doing it, that's what it is," Winslet says now. "I think by the time I did 'Eternal Sunshine (of the Spotless Mind),' I was getting it. It was just integrated more, and now I don't notice myself doing it, which I hope is good? Now for me, it's not a case of, 'Oh, did that sound English?' It's, 'Did it sound Delco enough?' That was more of a challenge than anything."

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This article originally appeared on USA TODAY: 'Mare of Easttown' HBO: Kate Winslet on her 'lovable, loathsome' role