If a movie is a solid hit, the studio usually sets up a deal for the sequel in a matter of weeks. But it's been nearly seventeen years since "Independence Day" became a box office blockbuster, and confirmed beyond a doubt that Will Smith was bankable star. Director Roland Emmerich has taken a while to get to work on a follow-up, but now he's making up for lost time - he's announced that not one but two "Independence Day" sequels are in the works.

Emmerich, who caused all sorts of mayhem in Washington D.C. in "Independence Day," is doing it again this summer when his thriller "White House Down" opens on June 28 (by which time, Emmerich and Columbia Pictures are probably hoping you've forgotten all about "Olympus Has Fallen"). While doing press for "White House Down," Emmerich spoke a bit about the upcoming "ID4" sequels, "ID Forever Part I" and "ID Forever Part II."

Emmerich's statements suggest the long gestation period for the sequels has been built into the story, which will take place about two decades after the events of the first movie. By this time, word from the alien invaders has gotten back to their home planet, and knowing that their advance force has been defeated, another band of ill-mannered spacemen are on their way to conquer the Earth. "We've rebuilt," Emmerich said. "But (the aliens) also do different things."

"The humans knew that one day the aliens would come back," Emmerich said. "And they know that the only way you can really travel in space is through wormholes. So for the aliens, it could take two or three weeks, but for us that's 20 or 25 years."

Emmerich also mentioned the invaders may be fighting against their own technology. "It's a changed world," he said. "It's like parallel history. (Humans) have harnessed all this alien technology. We don't know how to duplicate it because it's organically-grown technology, but we know how to take an antigravity device and put it in a human airplane."

And while some of the heroes from the first movie will be back, expect plenty of new heroes as well. "It's still some of the same characters, but also new younger characters; it's a little bit like the sons take over," Emmerich said.

One thing Emmerich didn't say is how many of the characters from the first movie will be played by the same actors. Bill Pullman is said to be on board, but there's no word if Will Smith will be returning (Smith is still a bankable star, while Pullman is a regular on the sit-com "1600 Penn" these days). And Emmerich may still be fiddling with the script: reportedly, the director and Dean Devlin (who co-wrote "ID4") have finished screenplays for the two pictures, but James Vanderbilt, who wrote "White House Down," has been brought in for a rewrite.

Once the smoke clears following the release of "White House Down," solid information will probably surface, but Emmerich has made it clear that after more than a decade and a half, the aliens are coming back to the nation's capitol, and they'll be no happier than they were the first time.