‘The Hangover Part II’ is director Todd Phillips’ follow-up to his 2009 smash hit ‘The Hangover,’ which became the highest-grossing R-rated comedy of all time and a certified comedy classic. The film follows Phil (Bradley Cooper), Stu (Ed Helms), Alan (Zach Galifianakis) and Doug (Justin Bartha) as they travel to exotic Thailand for Stu’s wedding. With the memory of Doug’s nearly disastrous bachelor party in Las Vegas still fresh—or at least well-documented—Stu is taking no chances. He has opted for a safe, subdued, pre-wedding trip brunch, with pancakes, coffee…and no alcohol. However, things don’t always go as planned. Two nights before the big day, at a fabulous resort in Thailand, Stu relents. One beer each. In sealed bottles. What could go wrong? What happens in Vegas may stay in Vegas, but what happens in Bangkok can’t even be imagined. Check out what Bradley Cooper, Ed Helms and Zach Galifianakis had to say about the film below. ‘The Hangover Part II’ is released in cinemas May 26th.

What was your most challenging experience on the film?

Bradley Cooper: I think unfortunately for Ed, it was the food.

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

Bradley Cooper: That lasted throughout the movie (laughs).

Ed Helms: It never fully went away. Maybe I should just leave the rest up to your imagination. Let’s just say my body exploded (laughs).

Zach Galifianakis: Ed had to borrow one of the monkey’s diapers (laugh).

Bradley Cooper: For his mouth (laughs)

Zach Galifianakis: I think in general just the city itself. Just getting used to the city for the first few days. The jetlag was a little bit tough, but once you got there and you got settled in, the people are so brilliantly nice that you feel welcome. It’s a great society, it really is.

Bradley Cooper: You know what was odd, what was challenging I thought, was the sheer number of people that were constantly on the set. There’s something about doing a production in Bangkok where there’s just tonnes of people all over the place. Todd Phillips, to his credit, thank God, likes a lean set and that just makes it easier to work, so that was a challenge, having to adapt to there just being so many bodies around all the time.

Is there a secret to keeping a straight face when filming with all you guys? It must have been difficult on a film like this.

Ed Helms: The secret is you do 500 takes sometimes (laughs). Because you can’t. There is no way you cannot laugh at Bradley or Zach, or whoever it is. It’s a problem, and you know who doesn’t like it, Todd Phillips (laughs). He gets so angry.

Bradley Cooper: Yet he laughs, a lot!

Ed Helms: He ruins takes by laughing, but when we start laughing he like, “we’ve gotta get this done!”

Bradley Cooper: The cool thing was that there was one moment in the movie where he kept the laugh, when Ed’s discovering his tattoo in the mirror and I broke into laughter in one of the takes and he was like, “keep it.” Then me and Zach incorporated it that Alan and Phil are laughing at the fact that Stu is finding himself in this predicament again. It was really fun to have the licence to laugh with that.

Zach Galifianakis: I like to laugh, you have to learn how to stop yourself. I think there’s also fatigue involved. When you’re tired it’s easier to zone out and get dull in the head (laughs).

Ed Helms: Or when you’re fatigued you just get really b*tchy.

Zach Galifianakis: That’s the other thing, it’s this crossing point.

Bradley Cooper: When Ed loses it, it’s probably the most infectious. He’s got a great giggle.

Ed Helms: I also just can’t stop sometimes.

How was it working with Crystal the monkey?

Bradley Cooper: Crystal turned out to be this miracle monkey, she’s incredible, she can do anything. When we were talking about it with Todd he was saying there’s going to be this drug dealing mule that’s a monkey and he’s going to smoke. I was like, “how the hell are you going to pull this off?” One of my favourite scenes in the movie is this montage, it’s Curtis Mayfield, right? It’s just one of the greatest scenes in the movie (laughs).

The only downside to Crystal is that she has very long claws. You don’t want to get Crystal around an elephant. There was one scene where we were walking down the street, there was an elephant and she sort of destroyed my shoulder.

Ed Helms: My favourite part about Crystal is her trainer is this guy named Tom who’s a sweet guy. Whenever he needed Crystal to do something, he would literally just say, “Crystal, jump on the table, jump on the table, jump on the table, jump on the table.’“And then Crystal would do it. So I don’t know if Crystal actually understands English or she’s just able to read the energy based on what he’s saying. I just found it so hilarious that her trainer would just repeat an English command over and over and over again until Crystal eventually did what she needed to do.

Did you get to improvise on this film?

Zach Galifianakis: We all have that temptation to go off script sometimes here and there. But this script for the sequel was pretty tight, we didn’t go off script as much as with the first film. You do every so often though, you throw out a fresh line here and there to keep it fresh, whether it ends up in the movie or not is not really the point, you’re not trying to hog the scene or anything. It’s just…for example to try and make Bradley laugh on his coverage, when the camera’s off me or whoever, mix it up.

Bradley Cooper: Yeah definitely. Also the process in how we make these two movies is that you have the scene, you shoot it one time and rehearse it, then literally every time we go back and work on the scene, we keep this, throw out that, then go back and do it. It’s not improvisation but it’s definitely re-working the scene, there’s probably not one scene that turned out exactly how it was written. That’s just not how Todd works.

What were you able to bring to your characters this time that you felt was unfinished in the first Hangover?

Bradley Cooper: I think that’s part of the reason why there was so much room for the second one, because there was so much unfinished. You really didn’t get to know the characters. The narrative was really this mystery, this ticking clock pressing them in the first one. I think the difference between that one and this one is this movie’s more about the dynamic of the three guys and you really get to know them. For example, for me watching the first one, it could almost be boiled down to one joke. The whole movie’s the setup and the punchline are 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 very caught up in what happened to Stu and how they dealt with that dynamic and what Alan did. Much more about that which I found to be a much more pleasing movie as a viewer.

Ed Helms: I think with the first movie we were defining those characters and discovering them ourselves. They were really kind of more in archetype, they were more just conventional archetypes in a way that we just added our own accents and inflections to. When it came time for this movie, it was very exciting because 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. You knew who they were, you knew what their relationships were and Craig Mazin, Todd and Scot Armstrong gave us a lot of fun stuff. It just fleshes these guys out. Getting to go to Stu’s dental office, it’s just more layers on these guys that is fun to explore. It’s just onion layers peeling back is a lot of fun.

Bradley Cooper: It was obviously a conscious decision by Todd to do that because the movie breathes more. There’s more room for it, just in terms of the timing of the cuts than the first one. This movie has a different musicality to it.

Zach Galifianakis: One of the big differences, I think what these guys had touched on, also the sequel, I think the audience, or Todd, or we all wanted to see us turning against each other a bit which was fun to watch. It kind of calls for it for Phil and Stu to clash. Even Phil and I have a relationship where I admire him but he gets mad at me and he’s been real gentle with me in the first one, but this one I think he’s at his wit’s end so I think that was something new that we explored. Also as Ed was saying, to go behind the scenes, to see people in their environment, to see Alan in his bedroom is really fun.