The actress plays a mother figure to her boyfriend's child in the new horror, and she admits being a mum to five-year-old Suri transformed her approach to tackling the tough role.
She tells Britain's OK! magazine, "Any child in peril means something different to me now I'm a mother. You go on alert and you know the sound of your own child's voice and cry immediately.
"Being a mother only gave me more insight. When you're a parent, you can't turn things on and off. It's kind of like you're raw. I think a tremendous amount of strength is revealed when you become a parent."