Bruce Willis in Live Free or Die Hard Frank Masi/Courtesy of 20th Century Fox

It's been nearly 20 years since the original Die Hard. Bruce obviously is not getting any younger. When setting up the movie's action set-pieces, did you ever have to consider Bruce's age?
I didn't really tailor anything to the fact that he is older now. I thought okay, I've got Bruce Willis, that's John McClane, and here's what I want to do. It's funny, sometimes he'd look at the storyboards, and see what we'd planned, and he'd say, "You know, Len, I'm not 34 years old, like you think I am." The guy is 50 and not 30. But, honestly, it didn't really play much of a factor.

But Bruce still magically looks the same.
The thing with Bruce is he gets kind of cooler with age. When the movie poster came out, I thought, Man, he looks cooler than he did in all the old Die Hard advertisements. He looked really good!

So here you are directing an iconic movie star in what is ostensibly Die Hard 4, a movie you've literally dreamed of making since you were a kid. There must have been a surreal moment or two, no?
Oh, sure. Many days on the set, with Justin and Maggie, everybody — it's weird to be part of a movie that's been around for such a long time, and for me to be directing, and discussing what John McClane should do. It was bizarre for me. There were moments when I'd ask Bruce to do something, and he'd do it in a John McClane manner; I'd have to laugh, because I grew up loving those movies.

Once you signed onto the movie, did you ring up your mom up and say, "See, mom? I wasn't wasting my time out in the backyard after all!"
[Laughs] That poor woman. Her backyard has been painted and sets have been built out there since I was probably 14.