Canadian actor, comic, writer, and director Seth Rogen got his start in the entertainment world by doing stand-up comedy as a teen. When he was just 17, he landed his first role in the TV sit-com Freaks and Geeks. From there, the Vancouver native has gone on to appear in a number of movies, including The 40-Year-Old Virgin (which he co-produced), Knocked Up, Superbad (which he co-wrote), Funny People, and The Green Hornet (which he also co-wrote). Rogen has also lent his voice to animated films, including Horton Hears a Who, Kung Fu Panda, and Monsters vs Aliens.
Rogen, 31, talked to WebMD about his new movie (50/50), balancing comedy and tragedy, his diet (let's just say he tries to eat healthy), his take on exercise (just don't make him leave the house), and whether laughter really is the best medicine.
Your new film 50/50 draws from your good friend and screenwriter Will Reiser's real-life fight with a rare spinal cancer. As both producer and co-star you've called it a "passion project." What sets this film apart from your previous work?
[Will and I] took the attitude that we had to make something positive out of this, something that we were proud of. It's not the type of movie that, when you hear it described, sounds like the best idea ever! We knew it was a comedy -- and that's what could set us apart as a movie. But it was important to us that we could really tell the story.
50/50 has many, many laugh-out-loud moments. How do you make fighting cancer funny without crossing the line?
We never wanted to be funny for the sake of being funny. It had to be consistent with the story and the characters. We really just tried to be as honest as possible and acknowledge that funny things happen. When your perspective is that of a comedian or comedy writer, you naturally see the funny things in any situation, and to us it was really about showing those funny things, even though it was such a terrible time. Balancing the comedy wasn't the hard part. Making sure the movie survived on a scene-by scene-basis -- like, the therapy scenes had to be right -- that was the hard part.
This movie also earns itself a five-hankie rating. Are you closet fan of "weepies"?
Not really. I like a movie that's both very funny and has a lot of emotional resonance to it. There aren't a lot of movies that make you laugh really hard, and make you cry.
WebMD has a cameo in the film! Did Reiser really look up his symptoms -- and odds for survival, from which the film gets its name -- on WebMD.com?
Will is definitely the type to search online, looking up all sorts of potential problems.
Is there a history of cancer in your own family? If so, what types, and do you take any specific health precautions now?
Not a huge history. Some. I try to eat healthy. And I ingest as few horrible chemicals as possible. And I wear sunscreen!
If you were to receive a scary diagnosis, what in life would you want to do first before facing life-or-death treatment?
I've done a lot of the things that I want to do. I think I'd just keep going.
Your fiancé, Lauren Miller, makes a brief appearance in 50/50, and you were interviewed together on Larry King's special, Unthinkable: The Alzheimer's Epidemic. [Miller's mother, age 59, currently has the disease.] What message would you like to relay about this degenerative condition?
I think a lot of young people don't realize Alzheimer's is not something that just affects our grandparents' generation. It will soon affect our parents' generation and eventually our generation. I don't expect people my age to spend a lot of time thinking about charities, but I want to get them to start thinking about what type of organization they'll want to dedicate more of their time, money, and energy to. Now that I've seen [Alzheimer's] firsthand, I think it's something that can use a lot of support.
For a comedian you've dipped your toes into some pretty serious waters. (In 2009's Funny People, a lead character also faces down a fatal disease.) Is there a dramatic actor buried deep within you trying to get out?
I don't know; I don't think so. One school of thought I sometimes subscribe to is the less funny something is, the more of a feat it is to make something funny out of it. I don't think every movie needs to be about something miserable and heavy, but I do think that's a very interesting creative endeavor. When I look at 50/50 I'm really proud of that aspect of it. It's about something very serious, and we don't shy away from it in any way, but at the same time we provide a movie that really makes you laugh really, really hard at times.
You often play lovable if loutish boy-men. How close are these guys to the real Seth Rogen?
You tell me! They don't feel like me. I mean, socio-economically they're all so different from me, I don't really relate to them...
Do you have a hero from the worlds of acting, comedy or otherwise?
I wouldn't be able to narrow it down to one person. That would be too hard. I have many heroes. But who has inspired me? Trey Parker and Matt Stone consistently do incredibly funny stuff. And if there's anyone I get incredibly jealous of, it's them.
Is a daily dose of laughter the key to good health?
I laugh a lot. And I feel relatively healthy. Not sure I look like it...
What is your best health habit? Your worst?
My "best health habit"? Oh, man, this interview is making me realize how unhealthy I am! [laughs] I try to exercise somewhat regularly. I drink a lot of water. I don't drink sugary beverages.
During your Green Hornet  days you dropped 30 lbs for the role. Was it difficult to do, and have you maintained the weight loss?
Let's say I've found a happy middle ground. OK! I'm not eating as well as I used to! Now you're making me feel bad! I feel like I'm talking to my grandmother!
What's your relationship with exercise now?
I use an elliptical machine, because I hate running. I hate exercising. So I have to do it in ways that I'm tricking myself that I'm not doing it. Anything I can do in front of a television or while playing a video game automatically works better for me. Anything that requires me leaving my house also is not good.
Which sense -- sight, hearing, taste, touch or smell -- do you most value, and why?
Probably sight, because that's the one I rely on the most. If I can keep one, that's the one I would keep.
You've got a few upcoming films this year -- Paul, Take This Waltz, plus a short written and directed by Beastie Boy Adam Yauch -- and you'll appear opposite Barbra Streisand in My Mother's Curse in 2012. Are you taking any time off? When and how do you relax?
I watch a lot of TV with my fiancé. I play video games. We go out to dinner. I cook.
Are you a good cook?
I'm getting better!
One last question: If you were convalescing in a hospital bed for six months and you could choose anyone from history, past or present, for a roommate, who would it be, and why?
Anyone? Groucho Marx! He'd be funny and interesting to talk to, the forefather of modern comedy.