"That's what Robert's really genius at. He gets these kids who are totally present and great little actors. I mean, here they are, they're children, and yet they're able to pull off comedy, and with the written word. It's a really rare thing," he said.
Piven says he also learned a thing or two while working on this family-friendly film because the theme is that you're the bad guy if you don't spend time with your family.
"I've been working without stopping for certainly this decade, and I'm taking my mom to Spain, and I'm going to spend some family time with my nieces. And the best news is, my nieces will have seen Uncle Jeremy act for the first time in 'Spy Kids,'" he said.
Right now, Piven is enjoying a double whammy of attention with his role in "Spy Kids" and the end of the HBO series "Entourage" after eight season ? for now anyway.
"I couldn't ask for a better ending," he said. "If there's a movie, fantastic, and, if not, I felt like we did everything we possibly could, and that's the best way to feel when you finish something."