11/09/2008 AT 07:00 PM EST
and Angelina Jolie
's twins may be only four months old, but they're already characters of their own.
"They're great. They're still so little, but they do [have their own personalities]," Jolie told reporters at the DVD launch for Kung Fu Panda
and the premiere of its companion adventure story, Secrets of the Furious Five
in Hollywood on Sunday.
Knox and Vivienne are "starting to get very smiley," their proud mom said. "They're at that [stage] where their personality really starts to shine."
As for the rest of the brood, they share a love of their mom's work. "I think it's a great film, and it's brought a lot of joy to children – and to my children, absolutely," Jolie told PEOPLE at the event. "My kids love it. They're very very proud, they've got mom [Tigress] dolls."
While Jolie – looking slim in a long-sleeved black Ralph Lauren dress and beige pumps with spiked heels – didn't let on whether she'd be attending any of President-elect Barack Obama's inaugural balls in January, she did say she was happy with the election last Tuesday.
"I was pleased to see how excited so many people were," she told PEOPLE.
At the premiere, held at Grauman's Chinese Theatre, furry Panda characters wandered around and danced while costars Jack Black and Dustin Hoffman chatted with fans and press. Jolie and the rest of the cast were on hand also as DreamWorks' Jeffrey Katzenberg presented a check for $1 million to the Conservation International in support of their efforts for the preservation of pandas in their natural habitat.
Jolie told PEOPLE shortly before the presentation, "We are so privileged in everything we get to do in this business, and the amount of money this film has made. To be able to share that and do some good always feels good."
See Knox & Viv's WORLD debut!