Even after winning an Oscar and an Emmy, Kate Winslet is still afraid of “fucking up.”

“I’m just like, if I don’t do the fucking homework, I’m going to be outed as a fraud. And so I better just keep doing it as much as possible so that I’ve got the fattest safety net. That’s my thing,” Winslet said in the Variety Streaming Room, presented by HBO.

Alongside co-stars Evan Peters and Julianne Nicholson, creator and showrunner Brad Ingelsby, and director and executive producer Craig Zobel, Winslet sat down with Variety senior entertainment reporter Angelique Jackson to discuss crafting extensive histories for the “Mare of Easttown” characters and staying authentic to the Philadelphia suburbs.

“I always try and give a character history even if it’s loose — where they grew up, whether their parents got divorced, did they have a parent who died, were their siblings around, what kind of socioeconomic background did they have, where did they go to school — some real basics,” Winslet said.

Winslet added that certain details about Mare’s background greatly influenced her portrayal of the character. For example, the fact that Mare lost her father when she was young informs her “shaky” relationship with her mother Helen (Jean Smart) and the way she grieved over the loss of her son Kevin (Cody Kastro).

“I found that as soon as I started mapping out the basics of who Mare was, it just turned into this just really thick canvas that just needed to not only anchor me but also provide a rhythm for the sense of family around Mare,” Winslet said.

Winslet also noted that she worked together with Nicholson on building Mare and Lori’s relationship, saying that it was likely they had a storied past and would have experienced kindergarten, their first periods, pregnancy, childbirth and the death of Mare’s son together.

“It was very gratifying to hear how everyone just felt like they believed that we were from there — that we weren’t just actors put in this place,” Nicholson said about the show’s suburban Philadelphia setting. “That was very moving for me.”

Winslet added: “The thing that we’re proudest of is that we were able to create a very real community within our show of people who have shared experiences and histories that bind them together and that in spite of everything they have all gone through within their lives, they — no matter what — look out for each other and stand up for each other.”

Watch the full discussion above.