"She is just into animals," Michelle Williams said of her daughter Matilda, 11, Monday night at the Los Angeles premiere of her film Manchester by the Sea

By Raha Lewis
November 15, 2016 12:45 PM

Michelle Williams‘ only child with the late Heath Ledger, daughter Matilda Rose, recently turned 11 years old — and she has a lot of love for one particular subject.

“She is just into animals. Real ones and stuffed ones. Saving them and sleeping with them,” Williams told PEOPLE Monday night at the Los Angeles premiere of her film Manchester by the Sea.

“We have a zoo in our apartment. We just added a cat to our dog and our fish. I feel like that’s a small petting zoo. I could get 50 [cents] a visit.”

The three-time Oscar-nominated actress, 36, jokes that she could probably monetize the number of critters in her home at any given moment, as long as she tailored her efforts toward a specific demographic.

“I think I could sell it to the 5-and-under crowd,” says Williams, who was joined at the premiere by Matilda’s godmother: close friend and former Dawson’s Creek costar Busy Phillips. “Maybe if I dressed up the cat and shaved the dog and sold them as some sort of novelty animal.”

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In the film, Williams plays the love interest to Casey Affleck‘s character — and Affleck, 41, was vocal about how much he liked working with the actress.

“I can’t talk when Michelle is talking,” he said to one of the reporters who was speaking to Williams on the red carpet Monday night.

He adds, “When Michelle is talking, I can only listen because she is such a great actress.”

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The feeling was mutual, as evidenced by Williams admitting she would’ve said yes without reading the script because of Affleck.

“I had wanted to work with him for a long time,” she says. “I had watched him on screen with all of his costars and I hoped that one day I would be one. So when this came around with [writer and director Kenneth Lonergan] and Casey, I knew I was going to do it, I didn’t have to read it to know that I was going to do it.”

But Williams’ most cherishes being a mom to Matilda. When asked what her favorite part of parenthood is, she replies, “Just hearing that word: Mama.”

Manchester by the Sea is in theaters Friday.