Bradley Cooper drinks in life

Bradley Cooper (from left) as Phil, Ken Jeong as Mr. Chow, Ed Helms as Stu and Zach Galifianakis as Alan star in Warner Bros. Pictures and Legendary Pictures’ comedy, “The Hangover Part II.”

Warner Bros. Pictures/MCT

Bradley Cooper (from left) as Phil, Ed Helms as Stu and Zach Galifianakis as Alan star in the comedy, “The Hangover Part II.”

PHILADELPHIA -- Barring the end of the world, or the even less likely scenario in which no one bothers to go out this weekend to see three guys wake up completely blotto, there will be a "Hangover Part III."

"Obviously, it will depend on the success of the second one," says Bradley Cooper, whose participation in the inaugural "Hangover" had more than a little to do with his rocket launch to stardom.

"You never know," Cooper adds, trying to sound cautious about the box-office prospects of the much-anticipated follow-up. "But if there's a sure thing. ..."

The first "Hangover," released in 2009 and likewise co-starring Zach Galifianakis and Ed Helms, went on to earn $469.5 million worldwide.

It was, in case you missed it, set in Las Vegas, where a bachelor party headed into a Bermuda Triangle of amnesia, anarchy and absurdist raunch.

In director Todd Phillips' "The Hangover Part II," the setting is more exotic: Bangkok. And the straits the trio find themselves in, believe it or not, are even crazier.

It's "Defcon 5 in Bangkok," Cooper says.

The actor, who dropped back in on his hometown recently, promises, however, that when the third "Hangover" comes around, it will break from the now-established formula.

Like the first, "Part II" finds its protagonists unable to piece together the evidently tumultuous events of the preceding evening. The fact that Helms' character, mild-mannered dentist Stu Price, wakes up with a tattoo across half his face is only the beginning of the mystery.

"I'll do a third (film) no matter what," says Cooper. "We've all talked about it, Ed, Zach and I, and Todd, and it really is about us coming together and agreeing on a concept. And we've all agreed to the tone of the third one, and what it has to be, which is completely not adhering to the formula of the second.

"That said, I do think that this one had to adhere to the structure, so you can get to know the characters more. They're much more fully developed. Now we can depart from that. ... So, for the third one, there will be no missing night. It will be an interesting thing."

Cooper already has had a good year, box office-wise. "Limitless," the deft, dark thriller about a slacker scribe who takes a drug that makes him preternaturally smart and successful, was No. 1 its opening weekend, and has now grossed close to $80 million domestically and $60 million overseas.

This is how Cooper's next year is likely to go, at least as things stand right now: After stops in Toronto, Cannes, New York, Los Angeles, New York again and Berlin, mostly to promote "The Hangover Part II," Cooper goes to Montreal to start work on "The Words."

"That's my buddy Brian Klugman, who I grew up with. I've known him since I was about 10 years old. We went to high school together," says Cooper. "And he wrote this little movie about a writer. Jeremy Irons is doing it, Dennis Quaid, Amanda Seyfried, Zoe Saldana ... it's great. I looked at (the screenplay) the other day and I realized I have a huge role."

He laughs.

"I thought it was much smaller. Oh, shoot. You know that feeling you get before an exam? That's me right now."

And after "The Words"?

"Five days on a new movie by another buddy of mine, Dax Shepard." And then "The Place Beyond the Pines," from "Blue Valentine" director Derek Cianfrance, with "Blue Valentine's" Ryan Gosling opposite Cooper. And then "Paradise Lost" in October. Yes, the Milton poem about the devil and the fall of man. And then there is a reboot of the dark comic-book saga "The Crow," to be directed by "28 Weeks Later's" Juan Carlos Fresnadillo.

Phew.

"Well, you know how it is," Cooper says with a grin, after running down his schedule. "None of that could happen, and then you'll see me walking down the street in a total daze."