Just as the time-honored treatment for a hangover is some hair of the dog, in Hollywood the time-honored way to follow a huge hit like The Hangover is to dive straight into a sequel. The staggering success of this summer’s Vegas-bachelor-party-gone-awry comedy, which took in $277 million to become the highest-grossing R-rated comedy ever, may have surprised the movie industry, but director Todd Phillips tells EW that, even while the film was shooting, he was already toying with an idea for a possible sequel. “You always have those days when you say, ‘If we did another one, wouldn’t it be funny if…?’ ” Phillips says. “Then once the movie tested so well, Warner Bros. came to me even before it was released and said, ‘Let’s do another one.’ ” Phillips, who’s currently shooting the road-movie comedy Due Date, with Robert Downey Jr. and Hangover star Zach Galifianakis, says he’s midway through working on the script for the Hangover sequel. Though he’s keeping the plot under wraps for now, he promises The Hangover 2, which will reunite the trio of Bradley Cooper, Ed Helms, and Galifianakis, won’t simply rehash the stag-party-disaster formula of the first film. “What people loved about The Hangover was not Las Vegas or the bachelor party but these three characters,” Phillips says. “I think you can take those characters and put them in other situations, and you don’t need the sell of Vegas and a bachelor party and all that other stuff.” As long, of course, as those situations involve a whole lot of booze and maybe a roofie or two.