Hattie’s lines come in a scene where she makes dolls with Kristen.
She warmed to her co-star over her week’s filming at Pinewood Studios and Frensham Ponds, in Surrey.
Hattie said: “Kristen is really kind and generous and nice. I got to see the film at a cast and crew screening.
“It’s amazing to be in a film.
“You feel a bit embarrassed when you see yourself, but I loved it a lot.”