As Anna in Frozen, Kristen Bell argues with her older sister Elsa (voiced by Idina Menzel). But off-screen, Bell is the one breaking up fights between sisters — her daughters Delta, 4, and Lincoln, 6.

“I will go like, ‘Well, Elsa would have never said that to Anna,'” Bell, 39, says in PEOPLE’s Special Issue, Frozen: Inside the Magic of Disney’s Frozen 2. “Literally! I’ll go, ‘What do you think Anna and Elsa would do about wanting to share this toy?'”