''Okay, everybody get undressed,'' the assistant director says through his bullhorn to the 150 extras strategically positioned on the Santa Monica shoreline. ''Remember, it's 85 degrees and this is a summer day at the beach.''
No, it isn't. It's mid-April, 55 degrees, and cloudy. The extras, recruited from local college campuses, have been shivering under blankets, sweatshirts, and beach towels for three hours, since 7 a.m., sacrificing their body temperatures for the greater glory of a Pepsi commercial that will mark the beginning of yet another summertime soft-drink marketing blitz. While Coca-Cola prepares to counter with a pop-music promotion that will include free cassettes and compact discs, Pepsi is filming its latest salvo in America's Cola War, appropriately called ''The Pepsi Chill-Out.''
Director Joe Pytka and his crews had hit the beach before sunrise, planting fake palm trees, constructing a fake hot dog stand, turning the previously barren stretch of sand into a bustling surf-side party zone. It will take the better part of two days for Pytka (who has directed Pepsi spots starring Michael J. Fox and Ray Charles as well as the ''Bo Knows'' Nike ads) to film the shots he needs for a series of ads that will run throughout the summer. Today's mission is to get a parade of celebrities (Bo Jackson, Dr. Ruth Westheimer, Annette Funicello and Fabian, Bert Parks, astrologer Jeane Dixon, and histrionic comedian Gilbert Gottfried) to deliver their pitch lines and do a little thing called the Pepsi Chill Dance, which actually seems more like a Pepsi Chill Gesture.
''Always do it with your right hand and to the side,'' Pytka explains to Fabian, who is having a little trouble with the movement your basic ''Walk Like an Egyptian'' hand jive and keeps stepping on Annette's foot.
''If I do it again,'' Fabian tells her apologetically, ''kick me in the shin.''
Celebrities come and go. Bert Parks, dressed in a tuxedo, gets the Chill move down cold. Bo arrives on purple splatter-painted crutches; after the take he spots Dr. Ruth behind the camera and scoops her up in his arms. Pytka, a notorious tyrant on the set, is grumbling because some of the extras don't look lively enough, saying at one point, ''Hey, guys, just for a moment, try to pretend you're straight and at least talk to the girls, okay?'' A crew member stands by ready to squirt the Pepsi cans with water droplets, so they'll always look enticingly cold.
By 7 p.m., with the sun and the temperature rapidly descending, the filming is almost over. Gottfried is improvising for the camera, screaming at the top of his lungs, while extras do the Chill Dance all around him. ''What is this? It looks like a bad karate movie. You could just whack the top of someone's skull off. You could hit someone in the neck and kill them instantly. How come no one's listening to me?''
Because, Gilbert, the director already yelled, ''Cut.''