After The Hangover became the surprise summer smash of 2009, a sequel was inevitable. But much of what the frat pack comedy had going for it the first time was shock value -- by way of a tiger, a baby, Mike Tyson, off-colour jokes and a generous sprinkling of full-frontal male nudity.

For The Hangover Part II, director Todd Phillips delivers a heaping helping of more of the same, seasoned with some Thai spice, fired up on a bigger budget and infused with those trademark cover-your-eyes-and-pray-for-humanity moments.(Warning: link contains some spoilers of an explicit nature)

The sequel finds the wolf pack reuniting in Thailand for dentist Stu's wedding. Since we last saw him, Stu (Ed Helms) has met Lauren: the gal of his dreams. Her family hails from Thailand, which handily justifies the new time zone.

Bradley Cooper, left, watches as Ed Helms riffs on Billy Joel's Allentown in a scene from The Hangover Part II. (Warner Bros. Pictures)

All the bros make the trip to Asia for the big send off: Phil (Bradley Cooper), Doug (Justin Bartha) and Alan (the now ubiquitous Zach Galifianakis). The only new element to the crew is the addition of Lauren's little brother Teddy (Mason Lee), an innocent, overachieving, pre-med student and sacrificial lamb.

After a slow beginning, we once again find Phil, Stu and Alan waking up in a hotel room -- this time a dingy one in the middle of Bangkok -- with no idea how they got there. Sub in a monkey for the original film's tiger, replace Stu's missing tooth with a Tyson-style face tat and we're off to the races. The goal: find the missing Teddy and make it back before the big wedding day.

Now it would be easy to criticize Phillips's slavish devotion to the original (I look forward to the inevitable YouTube comparison videos that run The Hangover I and II, side-by-side). But, what saves the sequel from a case of déjà vu is how the actors have grown into their roles.

As Phil, Cooper is now so laid back he practically falls off the screen. The scruffy-faced charmer continues to possess an easy charisma that makes up for his cockroach of a character. As the man-child Alan, Galifianakis finds a sweet spot between naiveté and desperation. He is a pot-bellied samurai of stupid, channeling idiocy to new heights. Needless to say, he and the monkey hit it off.

Finally, there is my favourite of the pack: Helms as Stu. Like his former Daily Show colleague Steve Carell, Helms excels as an everyman, albeit one with the capability of meltdowns of Dog Day Afternoon proportions. Helms is fine playing the too-nice dentist, but he's at his funniest when Stu is at his lowest -- whether it's his Ed Grimely-style hissy fit or his sardonic ode to Billy Joel's Allentown. (If you haven't seen it, I highly recommend checking out Helms in Cedar Rapids, a sweet and somewhat underappreciated recent comedy).

There are a couple other elements, including bizarre cameos from Paul Giamatti and Nick Cassavetes (replacing Liam Neeson, who had been a replacement for Mel Gibson). Yes, Ken Jeong returns as the high-rolling drug dealer Mr. Chow. Jeong says his cartoonish character is "commenting on the comedy," but I remain partial to his performance as the sad, former Spanish prof Chang on TV sitcom Community.

RATING: A comfortably crass and familiar comedy that improves on the original, The Hangover Part II gets three leering Mike Tyson heads out of five.

The Hangover Part II sees the return of the wolf pack, including, from left, Zach Galifianakis, Mason Lee, Bradley Cooper, Ed Helms and Justin Bartha. (Warner Bros. Pictures)