High life: Why laid-back losers are actor Seth Rogen's stock-in-trade

Stoned father-to-be, pothead on the run from the mob...it's cool, he tells Gill Pringle

Seth Rogen may have become one of Hollywood's most bankable actors, but the last thing he sees when he looks in the mirror is a movie star. "And please don't insult my intelligence by arguing that fact," snorts the 26-year-old Canadian comic. "I certainly don't feel like a movie star – not in this body anyway," he continues, letting out a machine-gun volley of laughter. "I think when you do comedy, you play by a different set of rules. No one really wants you to be in that good shape. Being in good shape implies a level of vanity that isn't necessarily funny."

Rogen certainly can't level that accusation against himself – and Hollywood's casting directors seem to agree. The actor/writer/ producer has had a busy year, after being thrust into the spotlight only 12 months ago, starring in box-office hit comedies Knocked Up and Superbad.

Not that he appeared out of nowhere; he's been honing his comedic timing as a stand-up since he turned 13. By all accounts his humour wasn't subtle, responding to hecklers with: "I'm 13. In 30 years, I'll be 43. And you'll be dead." At 16 he attended a casting call for cult TV comedy Freaks and Geeks, where he was introduced to the show's creator Judd Apatow – a meeting that would change his life. Rogen immediately exchanged his Vancouver high school for Hollywood and, when Freaks and Geeks was cancelled a year later, Apatow hired him as both writer and actor for his next TV series, the college dorm comedy Undeclared, later casting him in small roles in the movies Anchorman and The 40-Year-Old Virgin.

Recognising how audiences empathised with Rogen, Apatow then took his protégé mainstream, casting him in the lead role as Knocked Up's hapless father-to-be and producing Superbad from a script Rogen wrote with school-friend Evan Goldberg some ten years earlier.

"The success of Knocked Up hasn't really changed my life," Rogen insists. "I look exactly the same on screen as I do in person. I didn't go through an Ugly Betty-type transformation. If my career has changed then my actual day-to-day life hasn't. I've been living with my girlfriend for three years, and I really don't go out to bars or clubs much. It's not like I'm getting mobbed – I'm not Tom Cruise. The good thing about LA is that there's always someone more famous 100 yards away from me."

Apatow was not alone in recognising Rogen's talents: Sacha Baron Cohen hired him as a writer on Da Ali G Show in 2004, a job that Rogen was tailor-made for: "They were mostly British writers but us Canadians are pretty similar and that's one of the reasons we got along so well. As a Canadian, it's almost the best of both worlds. We know all of America's culture but we view it as outsiders the same way as British people, only we grew up with all-American TV shows, all-American movies and all-American news, even. But instead of watching it and thinking: 'Man, I can't believe our country's so messed up!' we watch it as: 'I can't believe their country's so messed up!'"

Rogen claims to have contributed to the Borat script also, despite not receiving any credit for it. But ask if he's offended at being omitted from the credits of one of the decade's biggest comedies, and he merely shrugs: "We're not credit-hounds. That's their thing, man. I helped them out. I didn't make that movie. That was their movie. I know I helped, you know I helped. I don't care if your average viewer doesn't know that I helped. Who watches the credits anyway?"

In any case, argues Rogen, Cohen is the funniest person in showbusiness. "Sacha is the only guy I've worked with who really invented a new kind of comedy. He thought of something no one else was doing, and he's the only guy that can do it. It's amazing because when you're writing this stuff, you forget that he also does it. He's such a good writer you forget that he's also able to pull all this stuff off."

Modesty aside, today Rogen is arguably more recognisable than Cohen, to the point where he runs the risk of over-exposure. Having penned the screenplay for the Owen Wilson vehicle Drillbit Taylor, released earlier this year, he also lent his distinctive deep voice to animated characters in Kung Fu Panda, The Spiderwick Chronicles and Horton Hears a Who!. In addition, Rogen recently featured in cameo roles in Step Brothers and Fanboys, and stars in the upcoming comedy Zack and Miri Make a Porno; plus the stoner movie, Pineapple Express, for which he also wrote the script, hits British cinemas this Friday.

Filmgoers are, of course, already familiar with Rogen in pothead roles, but in Pineapple Express there's a twist: Spider-Man's clean-cut James Franco has been cast as the unkempt drug-dealer opposite Rogen's own recreational pot user. If the history of comedy demonstrates that humour and good-looks rarely go hand-in-hand, then Rogen insists his co-star breaks the mould. "[James] kills me. He's so funny and he's handsome. Pineapple Express completely destroys people's image of him. He's by far the funniest part of the entire movie and there's a lot of funny stuff."

Unlikely to win approval from anxious parents, the film's slogan is: "Put this in your pipe and smoke it", while the New York Post captioned its review, "Romancing the Stoned". "I play the straight man. I'm stoned but I'm the smarter of the two idiots," explains Rogen. "When we wrote the movie, originally the roles were the other way. It's about these two guys who witness a murder and one's a process server who's a pothead and the other guy is his low-level dealer. When we first approached Franco, he was going to be the process server/straight guy and I would be his idiot pot-dealing buddy. And then we realised it wasn't as interesting as if we just switched it. You've seen me be an idiot pothead and you've seen Franco be a straight leading-man guy, but to reverse it instantly made it more interesting."

Rogen makes no secret of the fact that he smokes pot in real life, declaring: "More people I know smoke weed than don't, although maybe that's just the group of people I surround myself with. Its not like an integral part of my creativity or lifestyle – it's more like just having a beer.

"When you're from Canada also, it's viewed much differently there than it is in America. To me, the fact that a character smokes weed is not what I hang my hat on. Like when people see that I play a pothead in Knocked Up and I play a pothead in Pineapple Express and say, 'Aren't you sick of playing the same character over and over?' And to me they're completely different characters who both just happen to smoke pot. I would never say James Bond and Arthur are similar characters because they both drink! And maybe that's a more progressive view of weed, but it's how I view it."

The son of retired non-profit worker Mark and social worker Sandy, Rogen characterises his parents as socialists: "My dad worked for the British Columbia Coalition of People With Disabilities for most of my childhood. They're both amazing and have always been incredibly supportive. The only reason I'm here is because they always told me I could be. They moved to LA with me when I was 17 because legally they had to. I didn't live with them for long before they were able to move back to Vancouver, but I couldn't imagine how it would have been moving to another country without them."

Today, Rogen shares a Los Angeles mansion not with his parents but with comedy writer Lauren Miller. In keeping with his characters, he says: "I'm not the most romantic guy, although I do try. Before we met, I'd never really had a proper girlfriend and I thought it would somehow masculinise me, although it's actually done the opposite. Now I know about accent walls and the whole world of throw pillows."

It's a far cry from high school, he says: "I was definitely aware that any girl who gave me any interest, it was only because I was funny. But girls always say they want a funny guy – like you read an interview with like Jessica Alba and they ask 'What do you look for in a guy?' And she says: 'Oh, a sense of humour.' That's not true! What she means is: 'I want a guy with a good sense of humour, for an incredibly handsome guy.' That's what she's forgetting! They all say they want a funny guy but what they mean is: 'We want a funny guy who looks like a model...'"

Not that it puts off Rogen's fans: "They're all 20-year-old dudes," he says. "It seems I only relate to nerds in high school who can't get laid. I don't even have a stalker. I'm just not the guy that people stalk."

'Pineapple Express' opens on Friday