As a kind of acting, directing, editing, and even as a genre itself, comedy is seldom taken seriously. But as one of its most successful modern-day purveyors, Todd Phillips doesn't treat it as lightly: over the course of six movies as a director, he has steadily crafted one accomplished, straightforwardly entertaining comedy after another, launching careers and sharpening comedic voices, all by finding the right collaborators and then focusing their collective talents to maximize audience entertainment.

But after 'The Hangover' not only became the biggest comedy of all time, earned him some of the best reviews of his career and catapulted costar Zach Galiafianakis into the national spotlight, Phillips didn't sit around congratulating himself. Rather, he leapt feet first into 'Due Date,' a road trip movie that pairs Galiafianakis with another irresistible comedic actor, Robert Downey Jr., in a story about two mismatched travelers who are trying not to kill each other while making a trip across country.

Cinematical sat down with Phillips at the Los Angele press day for 'Due Date.' In addition to talking about why he went back to work so quickly, he discussed developing the film's odd, often hilariously mean tone, and examined the idea of collaborating with an actor like Galiafianakis as his own profile continues to rise.

Cinematical: You seemed to go into this pretty quickly after 'The Hangover.' What prompted you to jump right into this as opposed to doing 'The Hangover 2?'

Todd Phillips:
There was a bunch of things. One was being that I didn't necessarily want to do 'Hangover' and 'Hangover 2' back to back. Another was that I really wanted to work with Robert Downey, and it was an opportunity I knew I had with this script because we'd been developing this for a while. And obviously I wanted to work with Zach again – but there's a lot of reasons. I obviously love to do it, love to direct movies, and it was something that we could get going, and get Robert, and I was just like, you know what? I'm just going to do this in between [those films] so let's make it happen.

Cinematical: Robert is obviously a great comic actor, but he's not necessarily the first person people might think of as a straight man in a comedy. Other than perhaps his obvious general appeal, what made him the right person to put in the film opposite Zach?

Phillips:
I think Robert's probably the greatest actor we have out there. I mean, really – I can't think of anybody better. And for me, it was just so much about after 'The Hangover,' obviously I wanted to do another movie with Zach, I love him, and the ability or the opportunity to work with Robert, and put these two characters together. They're not a far cry from their characters in the movie, and I think those two personalities together was what got me excited about it.

Cinematical: Does Zach have an area outside of his comfort zone? He's pretty fearless.

Phillips:
No. Zach's probably the greatest comic actor certainly I've ever worked with, and he has a fearlessness – and that's the best way to put it – because that's all you look for as a comedy director, is fearlessness. Will Ferrell has it, Sacha Baron Cohen has it, and Zach has it in spades, and it just gives you so much freedom.

Cinematical: Zach has obviously had a lot of opportunities open up for him since 'The Hangover.' Have you felt the need or impulse to push him a little bit to get him to try things that are different than in the other films he's done?

Phillips:
I think that's up to Zach, the choices he takes and not necessarily playing [the same character]. A lot of people say that, like, oh, it's just Zach playing the same guy. It's really not; his character in 'Due Date' is entirely different than Alan in 'The Hangover,' and I'm sure that the movies he's made in between [are also different]. It's hard as a director to see an actor go and go do 'Dinner for Schmucks' or 'It's Kind of a Funny Story' because it's kind of like seeing your ex-girlfriend out dating, so I always hate that (laughs). But Zach will make those choices and see what roles appeal to him.

Cinematical: Audiences were really excited to see a sort of updated 'Planes, Trains and Automobiles,' But this movie has a lot more meanness than that one. How tough was it to find a balance between going for it as much as possible and not making the characters or situations so mean that it made especially Robert's character unlikeable.

Phillips:
I kind of think that's what makes the movie fun. That was for me as a director, you could say, you did a road trip movie already – you directed 'Road Trip.' But it's so different tonally, that as a director to challenge yourself to make those tonal shifts in the movie, that's what's exciting about it, and what Robert and Zach and I got into was how far can you go with a character and still have audiences love him. And audiences love him in the movie, and they love Robert Downey, and certainly the fact that it was Robert enables you to maybe spit on a dog's face or whatever he does in the film and get away with it. There's probably not a lot of actors that could pull that off. But I think that's what the whole film was for me, certainly as a filmmaker, playing and shifting tones in the movie; you go from a scene in the bathroom where Zach's crying at the loss of his father, and then in the next scene he's masturbating in the car next to Robert or whatever he's doing (laughs). That's what makes it work, I think.

Cinematical: Was finessing those shifts something that you had to find during editing, or was it something you would work on during shooting?

Phillips:
Yeah. I think as a filmmaker, it's something you're always doing. You're doing a little bit in the writing, and you're doing it a little bit on the set, and you're certainly doing it in the editing room, and it's all about finding that balance. A lot of times you try something and go, whoa, that took people out of the movie, and you kind of shave it and adjust it, and that's all it is.