The event celebrating the film's upcoming release was held Thursday night at the Smithsonian National Air and Space Museum where much of the family adventure flick takes place.
"Smithsonian" co-stars Owen Wilson and Amy Adams, and the movie's director Shawn Levy also turned out for the gala.
Levy and the cast participated in a press conference to promote the film at the Smithsonian Castle Friday morning, as well.
Asked what he thought about working on location at the venerable institution, Stiller told reporters: "I really enjoyed everything in the Air and Space Museum. It was just really fun to be around all that stuff; the real stuff. The real Spirit of St. Louis. We got to walk around the back one day and there is this incredible model airplane collection back there that nobody sees. Hundreds of model airplanes, detailed out. If you're into that sort of thing, it's kind of amazing."
So, how did Levy get permission to shoot parts of his movie inside the Smithsonian complex?
"I think it helped immensely that our first movie ('Night at the Museum,' which was set at New York's American Museum of Natural History) was well known enough that the Smithsonian knew before I ever met with them that we were going to treat their institution respectfully and with humor and wit, but with definite reverence, as well," Levy said. "Also, the fact that the first movie actually raised attendance at the New York museum (helped.)"
The director said he also promised not to break anything during the shoot.
"Night at the Museum: Battle of the Smithsonian" opens in the United States May 22.