Q: How did the idea for the film come about?

WILL: Well, the "Step Brothers" concept -- which is what people are calling it, they're not calling it a movie -- kind of came about after working with John on "Talladega Nights." Adam McKay and I just had so much fun with him, and we just decided 'if we can think of something, let's do another project together,' and John was really the catalyst in making sure that happened. Because, so many times, when you're working on films, you work with people that you click with and you like, and it's always like 'We're gonna be friends forever!' and then nothing ever happens. But we made a commitment to get together, and pitched a bunch of ideas, and this was the one; we figured out the story, and Adam and I went off and wrote it.

Q: How did you get in the mindset to play someone with a 13-year-old mentality?

WILL: It's not far from my current status. [It's] just kind of remembering back to those feelings of when you felt awkward and shy and adolescent. One of the things about being an actor is that we don't have to fully grow up, in a way, or at least I don't. [to Reilly] Do you feel that way?

JOHN: No.

WILL: Okay.

JOHN: I mean, yes, I do. I don't have to grow up either. In fact, it's the secret to success in acting.

WILL: I think it's the secret to success in life to not grow up, right?

JOHN: We were already kind of meditating on that mindset from the moment we sat down and started thinking up the stories. We basically just met a whole bunch of times over the course of a couple months and just tried to make each other laugh...

WILL: We shared a bunch of notes about stories we'd heard about or situations that happened to us, things like that, and just cataloged it all.

JOHN: Unlike a lot of scripts or movies where, from day to day, you're figuring out what the script needs, we'd been thinking about the script and the milieu of these guys for so long.

Q: Collaborating on this film, how do you decide to split up the material, and who's going to get to deliver which joke?

WILL: Honestly, we never keep track of that stuff. We had a couple read-throughs, and that's when you hear the rhythm of the script, and [then] if someone else needs more in a scene or a certain part of the movie, we try to make sure it's there and divvy it up. I don't know, I don't feel like we ever kept track.

JOHN: Not at all. In fact, that's one of the cool things about working with Will. For example, sometimes we'll be doing a scene, improvising or whatever, and while the camera's rolling, the director will [tell us to] say some crazy line, and we're not sure who he said it to, and we're like [to each other] 'you wanna say it?' And that's like really rare; most people, especially in movies, are so competitive, and they want to get on the set and be the one and take their shot. And me and Will are both like, 'you could say it, or I could say it' -- if it's funny, the movie's going to be better for it, no matter who says it.

WILL: We had the premiere last week out in L.A., and that was one of the more satisfying things, so many people came up to us and said, 'Wow, obviously you guys are funny, but almost every character has their moments.' Katheryn Hahn is hilarious, Adam Scott who plays Derek is really funny, Richard and Mary are great as the parents -- it really is seeing a bunch of people passing the ball around, and I think, as an audience, it's the most fun thing to watch.

Q: Which stories were drawn from your real experiences, and which one of you do you think is the most immature?

JOHN: We're both pretty childish.

WILL: We're both selectively immature.

JOHN: But at the same time, we're both pretty responsible. We're both good dads, we take our family life very seriously, and you know, Will is not one of these flaky, crazy comedian guys who has the happy-go-lucky personality in movies, and then behind-the-scenes is, like, a dark opium addict. He's actually just a good guy. And the stories, I mean, I'll say at this point, they've become Dale and Brennan's stories. Maybe they were inspired by something I remembered from my childhood or Will's when we were coming up with ideas, but they quickly became...

WILL: Like, I never had a samurai sword or anything. We just kept making lists of what would be so funny to see these guys do. I did have bunk beds, they never collapsed though.

JOHN: I wanted a samurai sword, but my mom was so stringent about no guns or weapons of any kind. And she was smart to do that. Because if we had the chance to find real guns, we would have been shooting. But what would happen is every time she'd leave the house, me and my brothers, as soon as the door would shut, we would just go hunting for all these toy guns and toy knives that my mom had hidden.

WILL: I used to have a Star Trek tracer gun that shot actual tracers. And my mom let me have a little dart gun and said 'you can have it, but don't ever shoot anyone close to the face.' And one kid was really giving it to me, and I was like 'I can't hold back,' and I shot him in the head with the dart gun, or it whizzed by his head, and my mom either saw it or heard about it and took it away. But I remember thinking, that was well worth it. He won't be bothering me again.

JOHN: Gangland style!

Q: Did you have any sibling rivalry with either of your brothers?

JOHN: My house was like "Lord of the Flies." It wasn't like one brother versus another brother, or "this brother is driving me crazy and why can't he let me have space!" I have three brothers and two sisters, so it was like all of us just trying to survive and have some shred of privacy in our lives.

WILL: My brother and I were always trying to mess with each other. It was definitely the usual kind of sibling thing, with possessions and 'keep your stuff on that side of the room' and that sort of thing.

Q: Besides John Stamos, who's the one dude you would sleep with, and why?

JOHN: Why do we need to go beyond John Stamos? We found someone we agree on!

WILL: Maybe Brody from "The Hills." But he's a little too young for me.

JOHN: Could it be anyone from history?

Q: Sure.

JOHN: Alexander the Great.

Q: When I saw the trailer, I wondered if you guys were going to come up with some crazy, contrived plot and have the brothers save the neighborhood or something.

JOHN: No, we didn't really have a plot.

WILL: Yeah, we wanted to avoid the wacky thing that they're all of a sudden, in an unreal way, CEOs of a company or something.

JOHN: That's partially what we're making fun of, the predictability of these kinds of movies, like "The Parent Trap." I would joke that the movie's like a cross between "Talladega Nights" and "Ordinary People." I think if it suddenly had a very earnest 'getting it together' sequence, I dunno... that's part of the joy of making movies with Will and Adam. How they take archetypical stories or cliches that are in movies, and then taking them to an absurd level or taking it up a notch to a place that seems completely ridiculous.

WILL: And we love the fact that they really only get [ever so slightly] better. They overcome some fears, and now have a karaoke business, but are they still living at home? Who knows, it's kind of all open-ended. Not to get too deep too, but Derek [Adam Scott's character] has supposedly everything, and then you see how unhappy and dysfunctional his life is. I like the fact that it comments on how it's all about achievement in America and being goal-oriented and getting to the top, and sometimes it's okay to just exist and function in society and be a productive, tax-paying person at the very least.

JOHN: Actually, we struggled with that a little bit. I remember thinking, 'how do we resolve it? What happens with these characters?' and the studio's probably sitting there thinking, 'yeah, guys, how bout a plot? It might be good to rap up these random scenes with a unifying theme.' I remember actually just saying to Adam, 'No, it should just be punk rock. The standard movie of this kind would just have them be new people by the end, but life isn't really like that.' We thought the more punk rock ending would be to have them pretty much where they were at the beginning of the movie.

Q: You've each played characters that have become iconic in their own way. If you could pick one to re-visit in a movie, who would it be?

JOHN: I would really like to go back to "Days of Thunder" and re-do that one. I know so much more about NASCAR now. A little bit of regret.

WILL: What was his name again?

JOHN: Buck Bretherton. And he is iconic, of course. Everyone knows me from that part.

WILL: I thought it was Buck Bretherton, Jr.

JOHN: No, his father was Buddy Bretherton.

WILL: I would love to be in "The Buck Bretherton Story." I mean, we might do another "Anchorman" potentially, and that'd be such a fun character to do again.

Q: Why would you go back to doing another Ron Burgundy movie? Did you just have more ideas with it over the years you've wanted to do?

WILL: We just had so much fun making that movie, and it was hard to get made, but what's been great is it's kind of taken on such a life of its own.

JOHN: It's beloved.

WILL: At least the feedback we get is that it's beloved. It's just one of those that feels like an evergreen thing that we could go back and do again.

Q: What're your thoughts about playing an existing character, like Dr. Watson in "Sherlock Holmes"?

WILL: You know what, that project is still kind of... we're still kind of figuring that one out, in a way. So, I can't really talk about that so much.

JOHN: I bet you're glad [the studio] announced it though.

WILL: Oh, yeah.

Q: John, are you planning on doing something else with Dewey Cox? I know the movie didn't do that great...

JOHN: I tell you what, that movie has found a real audience for itself. Maybe not at the box office -- we got killed by the competition when it came out -- but on DVD. I went to JazzFest in New Orleans, and among musicians, it is insanely revered, from Jack White to Robert Plant to Bonnie Raitt, like anyone I came across in my recent travels would grab me by the shoulders and say "Walk Hard! Me and my band and my roadies are obsessed with 'Walk Hard'!" Yeah, that was a blast, I'd love to play music and I'd love to be that guy again.

"Step Brothers" opens in theaters everywhere this Friday, July 25th.