LOS ANGELES—Nine years after Seth Rogen Seth Rogen left Vancouver’s Point Grey secondary school for the bright lights of Hollywood, he is still telling the world about the joys of growing up in his hometown. However, they are not necessarily things that are going to win him awards from the local tourism bureau.

Rogen and fellow Vancouver native Evan Goldberg wrote about their high-school high jinks in Superbad and are following up that hit with Pineapple Express. Their screenplay features a dope dealer (James Franco) and his customer (Rogen) running from killers who think the pair know too much about their business.

One scene called for Rogen to “French inhale” from a joint, which involved blowing smoke out and inhaling it back through the nose. Asked how he was able to do it so convincingly, he says, “Just growing up in Vancouver, you kind of learn that early on.”

The idea for the film came from Judd Apatow, who originally asked Rogen to audition for the TV series Freaks and Geeks when Rogen was still at Point Grey. He approached Rogen and Goldberg several years ago, asking if they thought the concept of an action movie set in the world of drug dealers would be something they would be interested in writing.

 “Judd said ”˜What about a weed action movie?’ ” Rogen says in an L.A. hotel room. “So Evan and I thought that could be rad and we thought if we could make a movie that was both a weed movie and an action movie and had a real kind of friendship story to it, that would be our favourite film ever.”

Although no one would confuse Pineapple Express with Lethal Weapon, Rogen and Goldberg came to screenwriting from a love of watching action films. Rogen says that when they were growing up they were more likely to watch films like Pulp Fiction than comedies.

“We are big fans of [Lethal Weapon writer] Shane Black movies. When we were young, Evan and I loved Die Hard and shit like that. In fact, those were the movies we wanted to make—and movies like Pulp Fiction and Reservoir Dogs, the kinds of films that had both comedy and violence.”

Rogen and Goldberg famously wrote drafts of Superbad while still in their first year at Point Grey. They made significant changes when Apatow asked them to turn it into a film. They did it without going to film school or reading books about screenwriting. Rogen says that changed when they approached the task of writing their second script.

They knew that they wanted to start the movie with a scene set in the 1930s that saw the U.S. military researching the effect of marijuana on troops. They wanted the scene to stay in the movie and went to the library to find out whether it would work.

“We found a book called The Art of Dramatic Writing,” he says. “It said, ”˜A thematic introduction will do.’ So we thought ”˜Great, now we can write a scene that has nothing to do with the movie, and we can say this book told us to do it.’”

Most actors who have worked on Apatow-produced or -directed films have admitted that the script serves as little more than a road map and that they are expected to bring the characters to life through improvisation. The 26-year-old Rogen, who until recently had worked almost exclusively on Apatow productions, says that Pineapple Express’s director, David Gordon Green, even allowed his lead actors to shoot one scene without a script.

“I always like to keep it loose in scenes, some more than others,” Rogen says. “For the diner scene, Evan and I wrote nothing except ”˜They talk in a diner’. A lot of scenes were improvised, but some that seem scripted were improvised and vice versa. I would say nothing is word-for-word how you find it in the script. I feel that the script is just a blueprint.”

Rogen has five films at some stage of development or production, including The Green Hornet, in which he plays the title role. They could go a long way in helping him avoid being typecast, given that he has admitted to smoking a few joints in his time and has played like-minded characters in Knocked Up and Pineapple Express. He says he isn’t concerned about being stereotyped.

“I don’t smoke weed on set all day,” he says. “After lunch you get tired. But, to me, the fact that the characters smoke weed isn’t what I hang my hat on. Arthur [the wealthy drunk from the movie of the same name] and James Bond aren’t the same because they both drink. To me my characters are different guys.”