'The Hangover': Retracing The Success Of A Few Crazy Nights

With 'III' on its way, learn how a surprise hit launched one of the most successful comedy franchises of all time.

This Thursday brings the unlikely success story of "The Hangover" to a close with the premiere of "Part III." The series, with three lead actors Bradley Cooper, Ed Helms and Zach Galifianakis, has had a cultural impact over the course of its four-year history, and now the cast's picture adorns a slot machine in the Las Vegas casino where they shot the original.

As you prepare for one last howl from the Wolfpack, take a trip back to where it all started and learn how we got "The Hangover Part III."

The Surprise Hit

The "Hangover" franchise has been so successful — the first two movies raked in more than $1 billion worldwide — that it's easy to forget that the first movie was never expected to be a huge hit. Warner Bros. knew the movie tested well before the release and got things rolling on a sequel weeks before the premiere. But when MTV News first spoke with a significantly less famous Wolfpack, they just hoped people would give their movie a chance.

"It's one of those movies, like certain drug movies, where you kind of want to do them after," Cooper said, predicting the cultural impact of the first movie. "I think everyone will leave wanting to go Vegas and do stuff like this."

The crew didn't know anything about WB's early sequel plans — aside from Helms' suggestion that it would take place in the lost city of Atlantis — but they seemed excited by the prospect of another "Hangover." "We don't know anything other than that's an awesome idea, and hopefully the movie will do well," Cooper said. "We'd all love to do it."

A Troublesome 'Two'

Before production even began on the sequel, "The Hangover Part II" had its first controversy to manage. Hot off of his leaked voicemail scandal, Mel Gibson was set for a cameo appearance, something that didn't go over so well with Galifianakis. Director Todd Phillips spoke with MTV News' Josh Horowitz about the ordeal.

"The only thing I regret is not maybe realizing. I've always made comedies, and comedies, in general, tend to fly under the radar, so maybe not realizing that we're not making a movie that's going to fly under the radar, that three months before we even started shooting it, people are going to weigh in with opinions and tell us how it's not going to be funny or how this is not a good idea," he said. "It's like, give us a shot to make the movie. Then weigh in."

One Last Ride

For the third and final "Hangover" movie, the cast and Phillips wanted to tie up the last loose end of the series. Galifianakis' Alan needed to grow up or least be able to make it on his own, without the Wolfpack. Cooper explained that the need to finish that story makes "Part III" the one to end it all.

"It's a departure from the other two, in terms of structure. There's no lost night. There's no after-effect of alcohol," Cooper said. "It's really a character study about dealing with this guy who has been really driving the narrative for the first two movies based on his shenanigans."

Check out everything we've got on "The Hangover III."