Credit: Melinda Sue Gordon/Warner Bros.

As members of The Hangover‘s Wolf Pack, Zach Galifianakis, Ed Helms, and Bradley Cooper are used to being put in uncomfortable situations — like in the first film, when director Todd Phillips wanted to use a real Taser on them during a scene in a police station until Warner Bros. lawyers put the kibosh on the idea. “My boys would have done it,” Phillips says now. “These guys are soldiers.”

But as Cooper says in EW’s Summer Movie Preview issue, nothing quite prepared them for the grueling experience of filming The Hangover Part II, the upcoming sequel to the 2009 comedy smash. The cast shot the film for nine weeks in sweltering, chaotic Bangkok, Thailand, where the Wolf Pack reunites for the wedding of mild-mannered dentist Stu (Helms), only to see things go horribly awry again. “We’d be on the ground, dirty, with fish blood dripping on us,” says Cooper, “and that became normal.” Phillips says the arduous shoot, which he compares, only half-jokingly, to the making of Apocalypse Now, created a tight bond among the cast and crew — a bond that was tested when word of a potential Mel Gibson cameo leaked last October, causing some dissension in the ranks. “It created some friction on an otherwise harmonious set,” says Phillips, who decided to swap in Liam Neeson for the cameo (only to have to cut Neeson from the film due to a scheduling conflict during reshoots). “On my movies, it’s really one big family — and you don’t want to rupture that kind of family over something like that.”

For more on The Hangover Part II and 100 other summer movies, check out Entertainment Weekly‘s Summer Movie Preview issue, on stands Apr. 15.

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The Hangover
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  • 99 minutes