Keira Knightley and Carrie Coon share they weren't 'allowed' to do Boston accents in 'Boston Strangler'

Keira Knightley and Carrie Coon recently revealed that they were forbidden from doing Boston accents while filming Boston Strangler.

On Tuesday, March 14, Keira Knightley and Carrie Coon spoke with PEOPLE at the  New York City premiere of Boston Strangler, at the Museum of Modern Art.

Knightley told the outlet, "We did 'standard American' Luckily, it's written in a Boston rhythm so you get the idea of Boston, but there is no Boston accent for me."

Coon joked, "Matt Ruskin, our writer/director, is from Boston and very insistent that anybody who is not from Boston was not going to be doing an accent, because he claims he's from Boston and he doesn't have an accent. But he does."

The 42-year-old added, "The movie is really written in the rhythms of Boston accents, so it was very hard to resist. So I was doing a kind of general American 1960s-something. But I was really looking forward to the Boston accent."

Knightley, who is credited for starring in Pride and Prejudice, continued, "All of the actors were very disappointed. We all tried to talk Matt Ruskin, our lovely writer/director, into letting us do the Boston accent, and he was like, 'Absolutely not.'"

She further added, "So we failed, but I kind of hear him, because as I found out, people are very opinionated about that accent. There's a lot around it. So he was just like, 'We're not touching that.'"