Gerard Butler has seen these kind of odds before.

The Scottish actor stars in the March 22 release Olympus Has Fallen, playing a Secret Service agent who loses his role as the personal guard to the president (Aaron Eckhart) after he saves him from a car wreck but is unable to rescue the first lady (Ashley Judd). When the White House gets infiltrated by a North Korean paramilitary group (led by Rick Yune) posing as a South Korean delegation, Butler's Mike Banning soon becomes the nation's last best hope, as mega artillery begins to implode America's seat of power.

The role of powerful and desperately outnumbered underdog helped catapult Butler to fame six years ago, when he starred as the Spartan King Leonidis in 300. The actor announced last summer that he wouldn't return to feature in the film's anticipated sequel, but as he tells The Hollywood Reporter, it was simply a matter of scheduling.

"I wasn’t really available to do 300. It was hard to work out the dates," Butler says. "I think that’s going to be a great movie, and I love that team of people. 300 was my most special moment ... it was my bar mitzvah."

The following interview has been slightly edited and condensed.

The Hollywood Reporter: Do you think you could be a Secret Service agent and put your life on the line for someone like the president in real life?

Butler: I think I could do it. I think it would be a pretty fascinating job, but I think that it is interesting to have to live with that concept every day, that it’s your job to die for another individual or another group of individuals. But there’s something heroic in that as well. On top of that, it seems it’s a very engaging job, there’s so much to learn, there’s so much knowledge required and talents and training that the guys that I spoke to that do it, they loved it.

THR: Ten years ago, this movie would have been about al Qaeda trying to get the president. So as the villain of American foreign policy changes, so do the villains of the movie.

Butler: Otherwise nobody would go see the movie. Twenty or 30 years ago, it would have been about the Russians, 50 years ago it would have been the Germans. If you made it about the Spanish, people would go: "I don’t get that. I don’t really feel a threat from Spain right now." But it’s a good point because it’s all about making the story, this geopolitical climate, as plausible as possible and making the attack -- the meticulous calculation, the genius behind that -- as plausible as possible.

THR: When you look back on American movies in wartime, the enemies are stereotypes. That’s a danger, a trap that I don't think you fall into here.

Butler: It is a danger, but because what happens here is so brutal and appalling, we had to make out that even though they have causes that are real to them, what they’re doing is so ridiculous that you don’t really spend time getting to know them. We want to make Rick Yune -- Kang -- a well-rounded character. You understand his motivations and how he is with his people, but other than that, often watching as little of the villains as possible keeps that mystery. It sucks you in more. The second you have your villain standing up and giving speeches about his politics and his viewpoints, every second you watch that, the threat dissipates, I think. So we limited that.

THR: You do a lot of different kinds of movies; do you feel like you don’t get enoughcredit for doing that?

Butler: Sometimes. I think some people appreciate it and some people don’t. I’ve watched many different actors who are great at what they do, they’re all good actors, but they generally do the same thing. But I always thought, "How cool would it be to show people, because you can, all different kinds of things?" From musicals to animated movies to comedies to dark comedies to drama to thriller to big action movies. And I think some people appreciate that and probably some people don’t.

THR: Is that why you decided not to do the 300 sequel?

Butler: No, not really. I wasn’t really available to do 300. It was hard to work out the dates. I think that’s going to be a great movie, and I love that team of people. 300 was my most special moment.

THR: That was the movie that made you a star.

Butler: (Laughs.) Yeah, it was my bar mitzvah.

THR: The production built a huge White House in Louisiana, and day by day, you were destroying it. That must have been weird to watch.

Butler: It was weird to watch it go up for me, but especially for people in Shreveport, and it was even weirder to watch it come down. Because then we were just blowing up the guard boxes and the whole White House. I fly helicopters sometimes, and I flew over there when it was just destroyed and it was amazing to see the wreckage from a bird’s-eye view. But it was also really cool.

THR: In my neighborhood, there’s still a gigantic billboard of you in Playing for Keeps. I always walk past it and think it must weird to see oneself that big.

Butler: I still find it weird. Sometimes you say, "Good, there’s a billboard!" I want to see as many of them as possible to help get the word out about the movie. And then other times, you go: “Wait a minute, that’s me. I’m Gerry. I grew up as a little kid in Scotland peeing my pants, and now I’m up here on a billboard in Hollywood." The first time I ever saw it was when I played Attila the Hun, which was a miniseries for USA Network. Seeing myself up there, such a buzz.

THR: And Attila the Hun isn’t the most glamorous.

Butler: Well, listen, it was for America, so we turned him glamorous. Long hair, dark eyebrows, beard -- this really intense look. Tanned face. Not really what Attila probably looked like.

THR: Olympus Has Fallen is going to be one of those movies that will play on cable TV on the Fourth of July and Presidents Day every single year.