In the movie, adapted from Rachel Yoder’s best-selling novel of the same name, Adams plays an artist who has given up her career to stay at home with her two-year-old son.

Isolated in the suburbs and struggling to connect with her new identity, Adams’ character, simply known as Mother, starts noticing changes within herself.

One day fuzzy hair is covering parts of her body, another, she notices two neat rows of nipples on her belly. Her teeth feel sharper, sense of smell heightened, and she can’t resist the urge to join the neighbourhood dogs on late night outings.

“It is a very physical role,” Adams said at the movie’s London Film Festival premiere on Wednesday.

“I was a dancer, so I always think about movement and how a character lives in my body. This one specifically felt very freeing because … I wasn’t thinking a lot about how I looked or what was needed from that. It was just really connecting with something primal inside of me, so there was a lot of freedom in it,” the 50-year-old, six-time Oscar nominee, said.

The toddler in the film is played by twins Arleigh and Emmett Snowden, who had no previous acting experience. The film team turned the production into a game for the boys, writer-director Marielle Heller, whose credits include 2018’s “Can You Ever Forgive Me?”, said.

Working with children and animals came with complications but also brought joy and a sense of spontaneity, Adams and Heller said.

“You could never really predict what was going to happen on any given day. It kept you very present,” said Adams, adding “I kind of relate it to giving birth because I kind of forget the painful parts and only remember the beautiful parts. And then we have this beautiful film that I’m very proud of.”

“Nightbitch” begins its cinematic rollout on Dec 6.