The 32-year-old actress, who has a five-year-old daughter, Suri, with husband Tom Cruise, takes on the role of a mum in the new flick by Guillermo del Toro.
Speaking to Access Hollywood, she said: '[The movie] does reveal the strength of a mother and something that I feel was hard for me to understand before I became a mother.
'That instinct to… you fight at any costs for your child.'
The former Dawson’s Creek star added that she was thrilled to work with Del Toro on the film.
She said: 'In Guillermo's movies, his female characters are very strong and they're not running around screaming and afraid. My character fights at the end. That rang very true to me.'