NEW ORLEANS - It seems appropriate that when we see Jay Baruchel on the set of "This Is The End" for the first time, he's sitting off to the side of everything, by himself, reading one of Brian Lumley's "Necroscope" books.

After all, one of the key dynamics in this film is between Seth Rogen and Jay, their old friendship a point of contention now that Rogen has become a huge movie star. Jay still lives in Canada, and he only comes to LA occasionally when he has to do it for work. On one of those trips, he hooks up with Seth for the first time in a while. It's immediately awkward, and it only gets worse when Seth talks Jay into going to a big-ass Hollywood party at James Franco's house. Everything Jay dislikes about Los Angeles and Seth's new life is crystallized in one awful evening, and when the world ends outside and people start dying, it seems like a natural escalation considering what's already happened between them.

Now, when I say "Jay" and "Seth" so far, I'm talking about the movie versions of those characters. Everyone is playing themselves here, but the biggest question about the film is just how close those versions are or aren't to the reality of who these guys are and how their friendships really do work. Baruchel has managed to stay somewhat removed from Los Angeles in real life, and certainly much of what we see in the film is based on the way people perceive these guys. That tension between reality and perception is one of the main sources of comedy in the film, and it seems like part of what everyone enjoyed while shooting it.

Baruchel told us that the original short film that inspired this film began when a friend of theirs, Jason Stone, was graduating from USC. He wanted to create a short film that could get him some jobs. He came up with the original idea with Evan Goldberg, and so for two days, they shot a short about Seth and Jay stuck in an apartment after the Apocalypse, bitching at each other. The final version of what you'll see in theaters this year captures the spirit of that short, but it's much larger in scope.

The other thing that seems right about Jay's choice of reading material is that there is a surprising amount of blood and gore in the film, and that makes Jay reading one of Lumley's "Necroscope" books feel right at home. He's a horror fanatic, he told us, and he seemed to be enjoying the overall experience. He said that he'd been especially excited to watch KNB work on the set. "I’ve been a fan of all the shit that they’ve worked on because I was a big Fangoria kid all through high school. So, yeah, it’s the best when I get to see all sorts of arterial spray and all sorts of gross shit. I’m a kid in the candy store."

Baruchel described how the versions they're all playing in the film have been approached. "I think they take the aspects of our personalities that are most conducive to punchlines and story arcs and exacerbate them, so it’s a tightrope. There’s definitely some stuff I do or say in this movie that the real Jay wouldn’t do or say. It’s strange. We are ourselves and we’re not." He admitted that it can take some tricky navigation. "I come up against conscience issues. One of the things we decided, because I’m getting married in September, and since Seth is married and Danny is married, is that none of us have any significant others in this because that would be entirely too much to explain, and who the hell really cares?" He says that each of them were exaggerated in very specific ways, and that in his case, "They definitely pounced on the self-righteous holier than thou aspects of me. There’s a lot of preaching in this."

Of all of the actors in the main ensemble, it seems to me that Jonah Hill is the one who is playing the most dramatically refigured version of himself. He said it was an easy decision to make, though, when they first approached him about the film. "There are a few people in my career I've been lucky enough to work with who I would do anything for, and Seth and Evan are those guys. If they ask me to show up, I show up. It doesn't really matter what it is."

In an early draft of the script I read, the Jonah they had written was extra-sarcastic, angry, and openly combative with Jay in particular. The version in the film is fairly different, though, and that was thanks to some feedback from Jonah. "I wanted to play a version of myself who always saw the sympathy in a situation, someone who was overly sympathetic to everything. I poke fun at myself. Obviously everyone does in this movie. I went to dinner with an actor who was shooting out here the night before we started shooting, and he had a big diamond stud earring in his ear. So the day we started shooting I said I wanted to wear a big diamond stud in my ear, and thankfully they let me do that."

The idea that Hill basically confiscated someone's real earring makes me cackle, and it's that sort of inside-baseball detail that makes this a special sort of ball-busting. I can't imagine these guys would be comfortable enough to do this with just anyone who showed up, but this is a very tight-knit comic community, built over time. "My college experience was making movies with these guys. We all started out together and have grown and evolved in different ways. To have everyone assembled together for a movie like this is rare."

Thanks to "Moneyball," Jonah's career is full of some new and different opportunities, and he acknowledged to us that things are changing. "I know this is my last comedy for the next year, year-and-a-half probably, so it feels like a cap to my early twenties. I don't know how to put it without making it sound like it wasn't important for anyone else, only me, but it's rare to get to work with this many people you've known for years and years and years. The next three things I'm doing are more hardcore, emotionally, and this is really fun. It's cathartic and fun, there's no other adjective I have for it. There's no pressure. it's really just a laugh."

When I saw him later in the morning at the craft service table, he re-emphasized it with a big smile on his face. "Seriously. Easiest shoot ever."

A respected critic and commentator for fifteen years, Drew McWeeny helped create the online film community as "Moriarty" at Ain't It Cool News, and now proudly leads two budding Film Nerds in their ongoing movie education.