He often plays serious sorts, but Ethan Hawke's actually a pretty bubbly guy.

In "Daybreakers," Hawke plays a scientist who's also a vampire. In the film, there are more vampires than people — and they're running out of blood.

Hawke, who has been nominated for an Oscar for his acting ("Training Day") and writing ("Before Sunset"), spoke recently about the film, and what's cool about vampires.

Question: Why are vampires so popular now?
Answer: My feeling is it's kind of like westerns. People will always identify with them. They just go through a certain wave of popularity, then it burns
itself out and then it comes again. There's something psychosexual, and something about them, I don't know. It is strange how in the zeitgeist it is right now. You know, it wasn't when we started this movie. When I read this script, I literally remember getting it and going, "A vampire movie — that's interesting." If I got the script today, I'm sure I probably wouldn't have read it. I'd be like, "I'm not doing another dumb vampire movie."
Q: Ha. Interesting way to describe it.
A: The thing about this one that made it not just another dumb vampire movie is that it had an original hit on it, the whole idea that there are more vampires than there are humans, where eventually they would be running out of their food supply. It
becomes an incredible metaphor for what we're doing, whether the metaphor is oil or animal rights or whatever you want to do to it, the way we're destroying the planet is not unlike a vampire sucking the blood from the earth. There's something that makes it resonate in a way that lifts it beyond typical genre movie. I felt the same way about "Gattaca."
Q: What's the attraction of a vampire?
A: You kind of end up relating to the vampire, because he once was human.
There's something beautiful about that. At the heart of every bad guy thing, the ones that are really good, you understand where the bad guy's coming from. It makes it much more complex.
Q: Yet "Daybreakers" doesn't exactly skimp on the gore.
A: There is an allegory to it, but it's still a hard-core genre movie.
That's what the old John Carpenter movies were like. There's an allegory there if you're looking for one. If you're not looking for it, it's just a fun movie. It's not like it's "Animal Farm" or something.