LAS VEGAS — Don't look now, but the heated race for summer's biggest blockbuster has a dark horse approaching on the outside track — a dark comedy horse, that is.

Recently revealed photos and footage from Ben Stiller's "Tropic Thunder" seem to promise a demented masterpiece along the lines of his last writing/directing/starring effort, the 2001 cult favorite "Zoolander." The film tells the story of actors dropped into a real-life battle zone, thinking they're shooting a war movie with hidden cameras — and to spoof big budgets, Oscar-winning actors and overblown action scenes, he filled the August 15 flick with all three.

In a revealing chat that yielded some thunder of its own, Stiller talked about Jack Black's illegitimate water-buffalo child, declined to talk about Tom Cruise's cameo — that's OK, the news was all over by Thursday morning (April 3) — and explained why he was a hard actor for himself to direct.

MTV: This is a movie that has Jack Black, Robert Downey Jr., Matthew McConaughey, Tobey Maguire, Nick Nolte and a half-dozen other big stars in it. It sounds like "Ocean's Eleven" meets "Apocalypse Now."

Ben Stiller: [Laughs.] I like that. But I've never seen either of those movies, so I don't know what you're talking about.

MTV: You lie like a rug.

Stiller: [Laughs.] No, it's based on a lot of war movies. And I really love those films, like "Apocalypse," "Platoon" and those sorts of iconic films. ["Thunder" is] the idea of a bunch of actors going off to make a movie in the jungle, and then getting stuck out in the jungle for real and running into real bad guys. I thought that could be a funny thing.

MTV: Why do you think so many actors were eager to do this script in particular?

Stiller: Well, I think actors relate to [the plot] because so much of the time we're just doing ridiculous things, trying to seem real while doing them. There's a lot you can relate to as an actor, and I think that's why we got a lot of great people to be in the film.

MTV: When Clooney was making "Ocean's Eleven," he'd just call up this person or that person and get them to drop by. How did you get Matthew McConaughey — and Tom Cruise has a cameo — how did you get all these people?

Stiller: I asked George Clooney to call them. [Laughs.] No, they thought it was funny, and at the end of the day, that's what it was about. They saw an opportunity to do something that would be a little bit different. But I'm also excited because [the film has] Jack Black, Jay Baruchel — this young kid who's great — and Danny McBride, who's just sort of happening. It's a really good mix of established guys and new guys too.

MTV: What was your set like during the day that Tom Cruise showed up and put on that fat suit and bald wig?

Stiller: I can't even confirm that.

MTV: Really?

Stiller: Yeah, but it is a good surprise in the movie, though. He's amazing. I was hoping [the press] wouldn't follow him around and give that away, but what can you do?

MTV: You've got all these disparate, eccentric personalities, shooting in the middle of nowhere. You must have witnessed some pretty strange conversations.

Stiller: Well, sure — we had Nick Nolte and Jack Black! There was a lot of camaraderie, because we were off in these locations together, just hanging out. Nolte is just Nick Nolte, and the combination of Nolte and Jack and Robert Downey hanging out, sitting by the monitor, talking. Nolte's going to bring up stories about whatever movie he's done or his titanium knee he just got replaced. Meanwhile, Robert Downey's ordering Bubba's Burgers [in Kauai] from, like, two hours away.

MTV: "Thunder" is also the first movie you've directed since "Zoolander." What was the hardest scene for you to orchestrate?

Stiller: Well, there's a sequence in the movie where Jack Black is tied to this water buffalo.

MTV: Excuse me?

Stiller: Yeah, he's strapped to a water buffalo, and the guys are trying to break into this compound to rescue my character. He was strapped to this water buffalo in his underwear, and we had to do this sequence. There were probably four or five days where he had to spend all his time on this water buffalo, and it wasn't comfortable. One day, they went to get the water buffalo — her name was Bertha — and they saw that there was a baby water buffalo in her pen with her. She had given birth overnight!

MTV: So she must have been pretty cranky in the days before.

Stiller: Exactly. Nobody knew the water buffalo was pregnant. Jack had been strapped to her for the week before, so we felt like Jack sort of induced the labor. [Laughs.] We kept calling the baby buffalo "Little Jack."

MTV: It's not easy filming a movie with a pregnant leading lady.

Stiller: Well, she took a two-day maternity leave, and that screwed up our filming. But then she came right back to work, looking much more svelte. And Jack still supports the child.

MTV: What's the one scene from the flick that you're most excited for the world to see?

Stiller: Well, there are a bunch of scenes that I enjoy in the movie that are a little bit out there. There's a scene where my character is talking about having played this mentally impaired farmhand who can talk to animals, in a movie called "Simple Jack," that he thought he was going to win an Oscar [for], but [instead, it] was one of the worst movies ever made.

MTV: Since this was a Ben Stiller production, what was the hardest direction that you gave yourself?

Stiller: Probably the hardest thing was getting myself to come out of my trailer when I was upset with me. That standoff lasted a long time. Everything came to a halt until I finally forgave myself. Then we made up with each other, and I walked out of my trailer, hand-in-hand with myself.

MTV: You're due to start filming "Night at the Museum 2" soon. In your mind, what will be the biggest difference between the first movie and the sequel?

Stiller: Well, it all takes place at the Smithsonian Institution. They've closed down the exhibits at the Natural History Museum because they're updating it, so they send them all to storage at the Federal Archive, and everything comes to life there. There are a couple of big things that come to life — and those things are even bigger than in the first one.

Check out everything we've got on "Tropic Thunder."

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