The Zero Dark Thirty star tried to be as distant as possible when she started work on the film - but youngsters Megan Charpentier and Victoria Isabelle Nelisse just wanted to play with her.
She explains, "My character is definitely the reluctant mother and wants nothing to do with children... and in the beginning she's a bit of a b**ch, unlikable and selfish who grows a heart of gold by the end.
"I'd rather just hang out with kids than adults any day, but I tried to be a little removed from them in the beginning; I didn't want to scoop them up and love them because that's not quite the character and I wanted them to be a little unsure of me. But it didn't last long.
"We had little dance parties to the song Dynamite. Little Isabelle only spoke French and learned English throughout the shoot and became obsessed with that song, so we played it every day. She learned all the lyrics and we did dance parties in the trailer.
"The girls would make drawings for me and I posted them in my dressing room... I mean, how can you not love these girls?"