Seth Rogen: I wanted to know how idiots would respond to the apocalypse But the cameras didn't start rolling without considerable soul-searching by Rogen and his colleagues. We had a lot of conversations about whether or not it was a good idea that we were playing ourselves, whether it was stupid, whether it would destroy the movie and whether we'd be hailed as self-indulgent egomaniacs. He gives a rumbling laugh. We are, anyway, so that's fine. All the actors and crew thought this was what people would like most about the movie so we confidently told the studio we were going to do it anyway. And to their credit they let us get on with it. Rogen is a big man. He speaks in a booming voice and is blessed with natural comedy instincts. He uses the F-word a lot, wears thick-rimmed glasses, laughs loudly and, at 31, is a bona fide international star, having established himself as a writer-actor who so far has seldom put a foot wrong. All his films - they include Knocked Up, The 40-year-old Virgin, Superbad, Pineapple Express and The Green Hornet - have made money, which is the ultimate barometer of success in Hollywood. As written by Rogen and his longtime collaborator and co-writer-director Evan Goldberg, the raunchy This Is The End contains a lot of jokes at the expense of the actors" professional and private lives, whether it's rumours of Franco's homosexuality or Rogan's poorly-received performance in The Green Hornet. "The actors are portraying themselves in some weird way so they improvised a lot and everyone was willing to push it a lot further than I would have expected, which was a nice surprise for both me and the audiences," he says. James Franco, Jonah Hill, Craig Robinson, Seth Rogen, Jay Baruchel and Danny McBride Among the movie's many surprises is a jaw-dropping appearance by Emma Watson, who leaves no doubt about her desire to finally bury her image as goody-goody Hermione Granger from the Harry Potter movies. "We wanted to have some people nobody would expect to be with us and every time someone asks, "Why the hell is Emma Watson in the movie?," that's why Emma Watson is in the movie," he says. We thought it was funny to have someone who was the last person you would expect to be associated with us. And she was great. "On her first day I think she was a little thrown by how loose we are with our material because I don't think they did a lot of improvising on those Harry Potter movies," - he gives another big laugh - "but she very quickly got in the swing of it and was improvising as much as everyone else. One of her jokes is probably one of the most icky in the entire movie and she fully commits to it and it's one of the biggest laughs. Rogen talks with the easy confidence and intimacy born of his background as a stand-up comedian. A Canadian Jew, he dropped out of high school and performed his first stand-up gig at the age of 13 in a lesbian bar in Vancouver - he maintains he thought it was Ladies Night and was not aware of the audience's sexual orientation. He moved to Los Angeles and met up with Judd Apatow, who cast him in the starring role in his teen TV series Freaks and Geeks. When the show was cancelled he appeared in another short-lived Apatow series Undeclared and then joined the writing staff of Da Ali G Show in its last season. He also contributed to Sacha Baron Cohen's Borat and has gone on to write and star in some of the most successful comedies of the past few years. His formula for success is simple: "We make movies for us," he says. When we made Superbad we were like 18 or 19 years old and we were the people that the movie was intended for. Pineapple Express is about guys in their late twenties who don't know what to do with their lives and that's who we were when we made that movie. This movie is about guys in their thirties who are kind of stuck between their old lives and their new lives. So it's important to us to make movies that are targeted towards us and not towards other people.