No, but I knew about Munchausen by proxy and I found it fascinating. It’s such an aberration of nature for me. As a parent my instinct is to protect my kids and I’d never want them to feel any pain. We know about physical abuse but medical abuse is a very different thing. But no, I didn’t know about this particular case. My kids did and they were like, “Don’t play that lady!”

There had been many interviews with Gypsy Rose but there was very little footage of Dee Dee herself. People’s vision of her was as this monstrous woman but I found some amazing research material, including an interview with her when she was in prison. She’d seem OK, then she’d go into this fugue state and come back from it, and I thought, She’s seriously mentally ill. Then I found horrible videos about Munchausen by proxy with people smothering their kids or injecting them as well as interviews with kids who survived. I came to the conclusion that Dee Dee was terrified that Gypsy Rose would break away from her.

I just felt horrible afterwards. Even before scenes sometimes I’d say to Joey [King, who plays Gypsy Rose], “I’m so sorry”. But I think it’s important to bring more awareness to this. Kids are living with it and I’ve met a bunch of people who have said, “I didn’t even know there was a name for it but I know people who have been suffering from it”.

Yes, but I kind of saw this coming a long time ago. When I did Medium [in 2005] I thought the film business was becoming more and more tentpole movies and less and less small films. People were kind of snotty towards TV but I was like, “I don’t think that’s a good way to react, I think there are going to be good things happening in TV”. It was a strategic decision I made back then. Now there’s more and more content and that’s great for our business, plus they’re not making as many movies as they used to.

The Act is on STARZPLAY via Amazon Prime Video and Virgin Media from June 14. Read our full interview with Patricia Arquette in the August issue