Nick Frost and Simon Pegg of 'Paul'

"What's so weird about two guys wearing one shirt?" (Lenny Gilmore/RedEye)

Simon Pegg and Nick Frost may not be as geeky as their sci-fi-loving characters in their new film, “Paul,” but they can relate to their especially close relationship.

“We live in our own little world and we have our own little gags,” says Pegg, who also co-wrote the movie with Frost, “and we can be in a crowd of people and they cannot understand what we’re saying to each other.”

That shorthand bond already has served the long-time, off-screen friends—Pegg says Frost knows him better than his wife does—in cult classics such as the zombiefied “Shaun of the Dead” and action-movie blowout “Hot Fuzz.”

In “Paul,” opening Friday, Pegg is Graeme and Frost is Clive, two comic book fans whose road trip to see famous UFO locations (Area 51; Roswell, N.M.) hits unexpected levels when they’re joined by a laid-back alien named Paul (voiced by Seth Rogen). Frost, 38, says the film is the British funnymen’s “love letter to Steven Spielberg.”

At the Peninsula Hotel, Pegg (seen in the previous and upcoming installments of “Mission: Impossible” and “Star Trek"), 41, and Wright talked about life on other planets, limits to Justin Bieber’s popularity and why they’ll soon have to play characters who hate each other.

When I interviewed you guys about “Hot Fuzz,” you talked about how being action heroes let you look cooler than you really are. Why did you want to look geekier than you really are in “Paul”?
Simon Pegg: That’s a very good question.
Nick Frost: We’re going to our extremes. For you, Nicholas Angel [from “Hot Fuzz”] is like your hardest and most fierce and most athletic and Danny [from “Hot Fuzz”] is my most stupid. I think these two characters, Graeme and Clive, are our nerdiest and our characters in “Shaun of the Dead” were certainly our most stoned and laziest. I think we’ve been all of them at different times, and not necessarily all the ones I’ve played have been me or all [of his characters] have been him. I think you’ve got to bring a bit of yourself, even if it’s 8 percent, for people to believe it.
SP: Also they had to be [geeky] because when we came up with the idea, it was like, “Who would be the funniest people to meet an alien?” And it would be two alien freaks. Two people who were into that [bleep]. Paul even says, “You’re a sci-fi nerd, I’m an alien; we should get on really well.”

They couldn’t be star college quarterbacks.
SP: Exactly. They’d be like (macho voice), “What the [bleep]”
NF: They’d beat him to death.
SP: (redneck voice) “Where the [bleep] is that little [bleep], get him!”

If you woke up and suddenly had an alien pal who wants to hang out, what would you do with him?
NF: Let’s go to Giordano’s! [Ed. Note: They had deep-dish pizza for the first time the night before this interview.] Let’s have a pie!
SP: More pizza. He’d have to have [live exotic birds] on his though. “This is delicious!” The first thing would be just a lot of questions.
NF: I think we’d bring it to one side and we’d say, (whispers), “Just go home.”
SP: “It’s not worth it.”
NF: “Don’t let us pollute you with our filth.”