A sequel to the hugely successful 2009 comedy The Hangover sees the action move from Las Vegas to Thailand. The cast and director talk about hitting on a winning formula and about what audiences can expect from the follow-up.
Whereas the first movie saw Justin Bartha's character Doug on the verge of married life, in Hangover II it's the turn of dentist Stu, played by Ed Helms.
"The secret formula on this movie is that the main characters get to be awful and behave irresponsibly in a crazy, wild, wacky way and then simultaneously, as they find out about what they've done, they are horrified by that," says Helms.
"They're both party animals and sweet loveable guys at the same time and no other formula, no other story, no other narrative can actually pull that off."
The film reunites the original cast with director Todd Phillips, who also co-wrote the script.
"There's definitely pressure when you make a sequel," he says.
"You're living in the shadow always of the first film which was so well received and so funny. So there's definitely some pressure but it's a good kind of pressure."
The film has already attracted controversy and criticism. The original trailer was pulled from some cinemas because its content was considered overtly sexual.
And animal rights activists have complained about a scene in which a monkey appears to smoke a cigarette.
"She did do things in the movie that monkeys don't normally do, like smoking cigarettes but of course the cigarette wasn't really lit," says Phillips.
"We put a cigarette in her mouth and she pretends to smoke it and then we light it later in CGI."
The monkey, a 17-year old capuchin, is a Hollywood veteran. She has appeared in more than 20 features including Steven Spielberg's Indiana Jones and the Kingdom of the Crystal Skull and the Night at the Museum movies.
"She is one of the best actors I've ever worked with, in all seriousness, if not the best," says Ken Jeong, who plays Mr Chow, the Asian mobster in The Hangover films.
"She's the scene stealer of the movie, she's amazing."
Once again, the film relies on the shock value of crude and politically incorrect humour. The sleazy nature of the storyline is also enhanced by the location.
"We chose Bangkok for the same reason we chose Vegas in that it sounds like trouble and it sounds like there'll be bad decisions made in a city like Bangkok," says Phillips.
But at the heart of the film is a familiar tale.
On the eve of Stu's wedding, he goes on a wild night out with Phil (Bradley Cooper) and Alan (Zach Galifianakis) and chaos ensues.
Needless to say, the following morning they wake up with huge hangovers and no memory of the debauchery and mayhem that occurred the previous night.
"A lot of people have been hungover and they might have some dark patches of the night before," says Galifianakis.
"That's relatable and people like to watch people suffer."
The comedy pushes the boundaries in terms of taste and vulgarity, although that is to be expected from the genre and it is not meant for family viewing.
The film-makers made no attempt to tone down the sequel, in fact quite the opposite.
"The thing that would be more offensive would be if we actually worried what people thought and went out milder and more timid the second time around," says Jeong.
"I wouldn't want to be part of that."
Phillips adds: "We don't do bathroom humour, I'm not a fan of that kind of humour so there are some shocking things in it, but I never think of it as grossed out.
"You make a choice to buy a ticket to a movie theatre. We're not forcing it down anybody's throat."
The Hangover won the Golden Globe award for best film, in the comedy section. Expectations for the sequel are high.
"Comedies always get a short shrift in the film world critically, but I can't tell you how many people email me or come up to me and tell me: 'Your movie put me in such a good mood'," says Phillips.
"There really is value in making people laugh."
The Hangover Part II is released in the UK on 26 May.