Samir Hussein/Empics Entertainment/Abaca
05/06/2011 AT 06:25 PM EDT
Jack Black and his character, panda bear Po, crack up the Jolie-Pitt kids – but mom Angelina Jolie
can't seem to catch a break.
"They know when Mommy's funny and when Mommy's not funny," the Kung Fu Panda 2
star, 35, tells USA Today
. "They'll sit in a room and say, 'That's just not funny.' "
Jolie's kids – Maddox, 9, Pax, 7, Zahara, 6, Shiloh, 4, and twins Knox and Vivienne, 2 – became "part agents, part managers" for the actress, she says, and proved their understanding of the industry on set of the Panda
sequel, which arrives in theaters May 26.
Their opinions keep her "competitive," she adds, even if they would rather hang with costar Black. "I tell them, 'I know you like [panda] Po,' " she said. "'But come on – Mom's cool too, right?' "