In the film, you play Alan, the deranged, jockstrap-wearing, socially awkward brother of the bride. How in the world do you prepare for that kind of role?
Well, I wish I had a concrete answer to that. In my mind, I just gave him [a]history. So the history was that he used to carry records to raves for a DJ. And one time when he was at a rave 15 years ago, he dropped too much acid. He wasn’t born really dumb, but the drugs made him really stupid, and [he’s] missing a part of his brain that is responsible for normal social interactions. And then when we shot [the film], these other subplots [popped up], like that he’s not supposed to get near children. But that storyline is not that he did anything malicious. He just wanted to hang out with anybody that would hang out with him, and sometimes those were 12-year-olds. So it was never a sexual thing. It was just, hey, there are kids in the park skateboarding, so I’m going to see if they can be my friend. And the other subplot I think was the fact that he had this kind of adulation for Bradley’s character and wanted to be really good friends with him.
That’s a very specific character that you’ve created. Do you know someone like him?
There’s a guy I know named Zach Galifianakis. Well, I think we’re all guilty of it, [but]not to that extreme of wanting to fit in and wanting everybody to like us. We all know someone that is kind of the fifth wheel. So I wanted him to be — even though it was only four of us — I wanted him to be this fifth wheel. And the only reason that he is there is because his sister is the one that’s getting married. So it’s by force. If that had not been the case, the characters would have never been in the movie. That’s what I like about it. It’s this forced thing.
Was there a lot of improvisation in the film?
Yes. A lot. The one improv that will haunt me for the rest of my life, is the — I don’t know how you can put this poetically — is [the scene where I]make the baby [unknowingly mimic a sexual act]. So that was improvised not with a real baby obviously, but a doll. Often, when you work with babies, they have a life-sized doll. So I just did it. I was like, “Todd [Phillips], look at this.” And Todd, the director, was like, “Oh, we have to put that in the movie.” And I was like, “No.” And then he’s like, “C’mon let’s ask the mom if we can do it to a real baby.” The next thing you know, there’s this conversation and then she agrees, but my fear is that 20 years from now, I’m going to be walking in an airport, and some guy is going to tap me on the shoulder and go, “Are you the dude from The Hangover?” “Uh-huh.” “Well, I’m that f—ing baby.”
With Ed Helms and Bradley Cooper as your costars, I imagine it was often hard to get through a scene without laughing.
Bradley Cooper is a bit disciplined. But I get the giggles. And when I get the giggles, it’s non-stop. And Ed gets them too. So there were a couple of scenes where we had to stop. But I have to tell you, we were pretty disciplined. But that’s the whole reason to do it, so you can occasionally laugh. To laugh during your job is a dream come true. Not to get too heavy-handed, but my father always told me to combine labor and love, and there’s nothing more I love to do than laugh and make people laugh and [to]be able to do it as a job is just wonderful.
You strip down to your skivvies in the beginning of the film. Obviously, you don’t have a problem with on-screen nudity, do you?
That was another improv thing. In the script, it said tighty whities. And I’d seen that in movies before. I’d seen the chubby guy with the underwear on. And I said to Todd, I’ve never seen a guy wear a jockstrap in a movie, especially under a tuxedo. And as soon as I said it, someone’s pulling some jock straps out of a wardrobe trunk. And again, it was another thing I regretted. But for the sake of the joke, it serves the character. It just worked. My poor mother. I’d rather her not have to see her son naked in a film, but maybe if my body were better, my mom wouldn’t mind.
Looking at your film resume, you’ve had roles in movies like Corky Romano, Bubble Boy, and…Into the Wild. It must have been a departure for you to appear in a Sean Penn film.
Well, that movie came about because Sean Penn saw one of those earlier movies that I did about 15 times, he told me. So I didn’t have to audition. He just asked me to come do it.
He saw me in a movie called Out Cold, a snowboarding movie. [Into the Wild] was a bit of a departure. It was a very serious, grounded thing, which, to me, is a lot easier than doing comedies.
Because you don’t have the added pressure of trying to make people laugh.
You don’t have the layer of trying to make it funny. You’re just telling a story. You take away that layer, and it seemed a little easier for me. I would love to do that dramatic stuff. I love to make audiences cry. That would just be the best for me. I think getting people to arouse their emotions is a lot of fun, whether it’s crying or being scared.
But you have to imagine some of your fans went to the theaters to see Into the Wild, thinking, “Awesome! It’s a Zach Galifianakis film!” and got something completely different.
“Oh God! He’s not in a jockstrap!” I don’t know. You just take a job, and acting is kind of hard and you never know your next job is, so you kind of take jobs and hope that people go see it and that it’s good. But the whole point of the element of surprise is to be able to do things that aren’t the same all the time. It’s fun to do, that whole spectrum. Once you start doing the one thing, for me, it’s really, really boring…. The end of it is, if I don’t have a statue of me somewhere, then what’s the point?