After the widespread acclaim of their previous films “Shaun of the Dead” and “Hot Fuzz,” British actors Simon Pegg and Nick Frost return to theaters with “Paul,” a sci-fi road comedy directed by Greg Mottola. The Chronicle had a chance to sit down with the long-time friends to talk about working with a CGI alien, biting Sigourney Weaver and the differences between British and American-style humor.

The Chronicle: You guys have worked together in the past, but this is the first time you’ve written a film together. Where did the idea for “Paul” come from?

Simon Pegg: This idea came about when we were making “Shaun of the Dead,” and it just never went away. It was a kernel of an idea we had in the garden, while shooting the record-throwing sequence, because we wanted to work somewhere it didn’t rain [laughs]. We spit-balled the idea like it was a joke. It was like, “We’ll shoot it in America, that’ll be great. We’ll play two British tourists, and that’ll be easy because we can stay British. And there’s an alien involved because it’s the desert.” That was literally the pitch, and it just never

went away.

Nick Frost: Our next film pitch should be “A mummy and a werewolf in

Barbados” [laughs].

The Chronicle: How did your partnership form in the first place? Have you been friends for a while?

SP: It was 18 or so years ago [when we met]. My girlfriend was working at the same restaurant Nick was, and I think everyone at the restaurant was in awe of his

comedic talent.

NF: And also my waiter skills.

SP: You could spin a tray better than anyone. But my girlfriend was saying, “Oh, maybe you should try standup. My boyfriend’s a standup [comedian].” And she hooked us up. We met at a party. I took him out to his first gigs, and then we just started hanging out.

The Chronicle: So, fast forward to this film. How did you shoot the scenes with Paul, considering he was added in later? He’s in nearly every scene, so I imagine it was pretty difficult.

SP: It was an incredibly complex process. We had to figure it all out along the way. [We needed] a very physical presence in a CG character, who has an improvisational kind of feel and a conversational speech pattern with us. So we started with Seth [Rogen] in the studio in LA. Then we filmed him on video for motion capture. So when we were on set, we had an idea of how Seth was going to play him. But there was an animatronic puppet. We also used a small actor in a green suit, as well as a child actor in a green suit and probably

something else.

NF: A man holding a gray ball! There were [Light-Emitting Diode] lights as well. We’d use those for eye lines. I think we were quite keen on making sure—and I know it sounds like an obvious thing to say—but we wanted to make sure Paul was good. Because you could write the best script in the world, but if in Paul’s first scene he looks absolutely awful, people are savvy enough to think, “No … ” People just assume he’s a character in the film, which is what you want. We wanted people to forget he was CG and believe him as a character.

The Chronicle: “Paul” boasts quite the ensemble cast. Who was the most interesting to work with?

NF: Having Sigourney [Weaver] on the set the first day was like, “She’s the queen!” You would see her scenes coming up in the schedule, and you would show up to work and ask, “Is she here?” She’s an amazing actress. She goes out of her way to make sure she knows everyone, and she interacts with the crew and you think, “That’s exactly why you are where you are.” I got to bite her in the re-shoots we did, and I sort of didn’t want to commit, but she was like “No, bite me!” And I was like, “Well, all right” [laughs].

The Chronicle: Part of the movie is set at Comic-Con. Do you identify with the comic book crowd?

SP: It’s always infused our work. We’ve spent a lot of time at Comic-Con [throughout] the years and that was good for us because we had to see [our characters] in their element at the beginning of the film. We wanted to see them somewhere they fit in and where they felt confident before we ripped them out of there and put them in the middle of this crazy adventure. We’re very much the kind of people who go to Comic-Con, though we’re slightly more functional than Graeme and Clive. They’re a little co-dependent.

NF: We have other friends apart from each other. We have one other friend [laughs].

The Chronicle: A lot of your work to date is very rooted in genre, a lot like comic books. What is it about genre cinema that intrigues you?

SP: We always feel like you should write what you know. We were big zombie fans when we wrote “Shaun of the Dead.” We grew up watching these kinds of films. These are the films we want to make because they’re the films we want to see.

NF: From a personal point of view, I’m not even sure I think of it like that. We didn’t sit down and think, “What genre are we [going to] do?” It’s a case of what Simon said, writing what you know. There’s a certain security in that, and truth that can come from it.

SP: I think the key to “Shaun of the Dead” is it is a spoof, but it’s a spoof of romantic comedy. It’s not a spoof of zombie films. It’s all done very seriously. All the [parody] elements in that film are aimed at romantic comedy. We had a crack at the Richard Curtis kind of lovely warm rom-com—which we both love.

NF: I’ve been in one!

The Chronicle: Does it ever surprise you that your films are so popular in America? People seem to think American and British styles of humor don’t mix.

NF: Everyone finds a fat man falling through a fence funny no matter where you live. But there are cultural specifics [that] change. Where [Americans] would say Don Rickles, we would say Bill Forsythe.

SP: I think “Shaun of the Dead” is funny to Americans because it is British. It’s an English take on an American trope. “Shaun of the Dead” is us taking something very American and putting it in a British context, and it allows American viewers a way of readdressing those things they feel very familiar with. Same with “Hot Fuzz.” We’ve all seen that kind of movie a million times but not set in a small village in Gloucester. I think we all have the same sense of humor,

“Paul” opens nationwide on March 18. Check local listings for showtimes.