Ed Helms thinks 'The Hangover' is a "mystery movie".

The actor - who will reprise his role as dentist Stu Price for the film's sequel - understands why fans can't wait to see what happens in 'The Hangover 2' because he thinks it is more than just a comedy.

He explained: "'The Hangover' is, at its core, a mystery movie, and the movie itself is about finding out information and uncovering and digging for information. So, what that information is is what makes the movie so exciting. It's the reveals. It's the mystery.

"I think it makes a lot of sense that fans of the first movie are dying to know what those little nuggets of information are in the second one."

Ed - who stars with Bradley Cooper, Zach Galafianakis and Justin Bartha in the eagerly anticipated sequel - has promised the new film, in which the four friends go on a bachelor party to Thailand will be even better than the first.

He told Aintitcoolnews.com: "It has this sense of like, 'Oh my God, what have these guys gotten themselves into?' kind of thing, and the first movie just went to such crazy extremes, it makes sense that it would kind of stimulate curiosity about what other new extremes could this new one go to? All I can say to that is, we have built on the first one, and it goes much further."