Hey, Was That Gwyneth?

Like any James Bond parody, Austin Powers in Goldmember begins with a big chase scene: Austin on a winding road after a hot blond in a hot car. At the end of the scene, Austin turns to the camera--and we see it's not Mike Myers but...well, a major star who recently had dental work.

Audiences watching the movie, which opens Friday, will spot a dozen such "cameo" appearances. They'll find Gwyneth Paltrow, Kevin Spacey, Ozzy Osbourne, John Travolta, Britney Spears and (as a mustachioed prison guard) Katie Couric.

Cameos are almost as old as movie stars. In the 1928 Show People, Marion Davies doesn't notice that the fellow asking for her autograph is Charlie Chaplin. Bing Crosby and Bob Hope traded cameos in their '40s films. But this summer has a gleeful glut of celebs dropping in unannounced on other people's parties.

A couple of Camerons, Diaz (on a subway) and Crowe (on a bus), flit through Minority Report, directed by Steven Spielberg--who also shows up in Goldmember. Men in Black II enlists Michael Jackson and Martha Stewart--aha, they are aliens! In Mr. Deeds, Al Sharpton delivers a rappin' elegy and John McEnroe teaches Adam Sandler how to (mis)behave in New York City. Steven Soderbergh's Full Frontal features bits by Brad Pitt and his Se7en director David Fincher.

Like the "Easter eggs" (hidden extras) in DVDs, cameos are a cute freebie for viewers--an inside joke even outsiders can get. And stars enjoy spending a day or two working for scale and promoting themselves as good sports. Sometimes, a bit of deception is required. Says Soderbergh of his quest to land Pitt and Fincher: "I used each of them to get the other. I told Brad David was doing it; I told David Brad was doing it."

Jackson had declined director Barry Sonnenfeld's request to cameo in the first MIB. This time Jackson called Sonnenfeld. "He said he had found the first film very moving, and he stayed in the theater by himself and cried," says Sonnenfeld. "I tried to explain that I personally thought Men in Black was a comedy... but we just went past that."

Of course, a cameo's fun is in its surprise. So if you're planning to see Goldmember, don't read this story. Oh, sorry, you just went past that. --By Richard Corliss. Reported by Benjamin Nugent/New York