"It's such a well-oiled, as you say, iconic franchise, and one which I grew up with," Blanchett recalls. "On the first day of shooting, it was extremely surreal. I was watching the monitor as Steven [Spielberg] set up the frame, and I knew the iconography of the frame. I knew the trucks, I knew the layout, I knew the way these things were lit."

Recognizing such elements in person made it hard for Blanchett to do her job. "When I was meant to enter the frame, it was a real Zelig moment. So it's been fantastic, and so much fun. And my boys have had an absolute ball. I've got a couple more weeks."

Even her sons are sworn to secrecy. "I'll be shot and so will you. Don't joke, there's FBI people on the set."

Indiana Jones and the Kingdom of the Crystal Skull swings into theaters May 22, 2008.