When the Wolfpack wakes up in a dodgy Bangkok hotel in The Hangover Part 2, school teacher Phil (Bradley Cooper), dentist Stu (Ed Helms), and odd duck Alan (Zack Galifianakis) discover not a tiger and a baby like they did in the 2009 Las Vegas set. They instead discover a monkey and a human finger. The cast and director Todd Phillips -- who helmed Due Date in between the two Hangovers -- sat down recently to answer some questions about shooting in Thailand, evolving the franchise beyond a premise, and their chain-smoking simian co-star. Here's part one of what the fellas had to say!

Question: “So, Bangkok ... what was that like? What were some of the challenges of shooting there?”

Bradley Cooper: “[Laugh] I think, unfortunately for it, it was the food.”

Ed Helms: “I had a very serious hurdle to get past the first week, which was severe food poisoning.”

BC: “That lasted through the whole movie.”

EH: “Well, it never fully went away. And maybe I should just leave the rest up to your imagination. Let’s just say, my body exploded.”

Zack Galifianakis: “In general, I think the city itself, it was just challenging getting used to the city the first couple of days. Jet lag was a little tough. But once you got settled in, the people are so brilliantly nice that you feel so welcome. It’s a great society, it really is.”

BC: “You know what I thought was challenging: the sheer number of people on set. There’s just something about doing a production in Bangkok, where there’s tons of people all over the place. Todd, to his credit, likes a lean set -- which just makes it easier to work. So that was a challenge, just learned to adapt to how many bodies were around all the time.”

Todd Phillips: “I think in a nutshell, Bangkok is just a very busy, crowded, and hot city. So we just all had challenges dealing with that. But ultimately, the movie is about mayhem. Sometime to make a movie about mayhem, you have to go to mayhem. So I think it all found its way into the movie and helped.”

TP: “That was the debate. We spent a month sitting around saying, ‘How different should it be? Different or the same? Different or the same?’ In the end, people come to a sequel because of what they enjoyed about the original. In the end, which is what I think is right, you stick with the template of the first, but you make the stakes a lot higher, you make it a lot darker. The other thing we did, which I think is right, is to acknowledge the characters had already experienced this the first time. In the first movie, they wake up and there’s a tiger and a baby in the room -- then they go and have breakfast. They can’t do that this time. They know how bad it can get. So I hope we landed on the right blend.

Question: For Bradley, Ed, and Zack ... actors can sometimes feel like they left a role unfinished when they walk away from a shoot. Did you look at the sequel as a way to address that feeling?

BC: “I think that’s why there was so much room for growth in the second one, because there was so much undefined. You didn’t even really get to know the characters. This mystery, this ticking clock, really, took precedence in the first one. The different between that one and this one is that this movie is more about the dynamic between the three guys. You really get to know them. For example, for me, watching the first one, it almost all can be boiled down to just one joke. The whole movie is the set-up and the punch line is the credits. When you get to the end of this movie, I’m excited to see the credits, but that’s not what I’ve been thinking about the whole movie. I got really caught up in what happened to Stu and what Alan did. It’s much more about that, and so I find it to be a much more pleasing movie, as a viewer.

EH: I think the first movie, we were defining these characters and discovering them ourselves. But they were conventional archetypes in a way that we just added our own accents and inflections to. When it came time to do the second movie, just to echo what Bradley said, we were able to add dimension to these characters in a way because we’d already done the homework, we already knew what the relationships were.

ZG: “One of the big differences between the movies for me was…”

When Zack doesn’t finish his thought…

EH: “Your outfit?”

ZG: “Yes, my outfit. No, I think the sequel, what Todd and we all wanted to see, was us turning against each other a bit. It kind of calls for Phil and Stu and Alan to really clash. Phil and I have this relationship, where I admire Phil, but he gets mad at me. He was kind of gentle with me in the first movie, but in this one he’s kind of at his wit’s end.”

ZG: “Yeah, I think he’s going to have a lot of mental trouble for the rest of his life.”

Question: Todd, you seem to get Zack’s comedy timing and utilize it well. Do you give him a lot of room to improv on set?

TP: “Certainly, there are some improvised lines in the movie. But we don’t do a ton of improvisation on set. We do it off to the side, in the morning, where the three or four of us will offer ideas, take notes. And of course, when we’re shooting, these guys are always free to add here and there. A lot of people think it’s a made-up movie, lot of improv, lot of freedom, but it’s not.”

Question: “Mike Tyson is back as well. Why was it important to have him return and what was it like working with him again?”

BC: “Mike looked fantastic. He’d lost about 50 pounds. He had promoted the first one with us. We got to spend a lot of time with him, not just shooting the first Hangover. My memory of Mike is, the day before shooting his scenes, you’d see him walking around. He looked like was prepping for a fight. He had his headphones on, his robe on. He took it all so seriously.”

TP: “For me, it’s just that Mike is such an iconic part of the first Hangover. Sometimes when people talk about it, they say, ‘You remember The Hangover, that movie with Mike Tyson?’ The Hangover became very identified with Mike’s image. Personally, I felt it was really important to bring him back.

BC: “You know, Crystal turned out to be like this miracle monkey. She’s incredible. She can do anything. I remember Todd talking about it. He said there was going to be this drug-dealing mule who’s a monkey. It’s going to smoke, too, he said. And I was like, ‘How the hell are you going to pull this off?’ The only downside of Crystal is her claws. You don’t want to get her around an elephant. There was this one scene where we’re walking down the street and she sort of destroyed my shoulder, [scared by a passing elephant].”

Question: Todd, will the Blu-Ray include any raunchier stuff that just didn’t make the final cut?

TP: “I don’t know if there’s raunchier stuff for the Blu-Ray. This is my seventh movie, so I kind of know what the line is with the MPAA and how far you can push audiences. So it’s not like we have a bunch of raunchier stuff for the Blu-Ray. I think there’ll be some deleted scenes, but nothing that was cut out for being too raunchy.

EH: “Obviously, if you’ve seen the movie, we put things in because they’re too raunchy.”

TP: “We did do a couple of cool things [for the Blu-Ray], like [Ken Jeong’s character] Mr. Chow gives us a tour of Bangkok and how he kind of runs the joint. So we did special things like that, for sure.”