The British actress, 45, plays Delaware County, Pennsylvania, detective Mare Sheehan and to prep for the role, she would read local papers.
"So, I subscribed to the Delco Times, so I would read this newspaper every day, and there would regularly be some article about Wawa," Winslet told the Los Angeles Times’ "Envelope" podcast.
"It almost felt like a mythical place, Wawa," she joked. "And so by the time I got there, I was like, ‘Oh, it’s real!’ It was like Lapland [Santa's Village in Finland]."
"Walking into a Wawa ultimately felt, it was kind of an honor in a funny way because to me, that was the heart of Delco. To finally walk through the door of a Wawa, I felt like, ‘Ah, yes, I’m here! I belong! This is where it’s at!’ Wawa," Winslet recalled.
The Oscar-winner revealed she only bought a coffee but enjoyed "hanging out" in the store.
Winslet added that her "Mare" co-star, Evan Peters, regularly enjoyed eating Wawa's seasonal "Gobbler" hoagie.
"It was this gigantic sub, basically — or hoagie — and it’s like turkey and the stuffing," she said. "It’s basically a Thanksgiving meal in a hoagie."
Winslet previously admitted that nailing the specific Delco accent was challenging. "It is absolutely up there amongst the top two hardest dialects I’ve ever done," she told the LA Times. "It’s something that I have to work on truly every day."
She worked with her longtime dialect coach, Susan Hegarty, to get it down.
"I couldn’t really phonetically learn, I just had to keep hearing it, keep hearing it," Winslet said. "I mimic people a lot by accident. So I just needed to know that if I was going to be mimicking anyone, it better be the right sounds."