'SHOWGIRLS' IS SO HYSTERICALLY FILTHY, YOU'LL BE LAUGHING ALL THE WAY TO YOUR SHOWER TO REMOVE ITS DELICIOUS RESIDUE.

"Instant camp classic," giggled The New York Times about SHOWGIRLS. And how! It's been well noted that writer Joe Eszterhas lifted the plot of Showgirls from All About Eve, 42nd Street and Flashdance. It should also be pointed out that Showgirls owes a major debt to one of my favorite bad movies, Valley of the Dolls. What Eszterhas has done is combine the four femmes from Dolls into just two gals -- with schizo results. Elizabeth Berkley behaves like both a nice newcomer seduced by her boss and a self-destructive, psychotic bitch; costar Gina Gershon is both a sweet showgirl and a seen-it-all, show-biz monster. Even the stars we hear the filmmakers wanted for the Berkley and Gershon roles, Drew Barrymore and Madonna, couldn't have pulled off playing such split personalities. With two glassy-eyed doorstops in the leads, Showgirls is unadulterated farce from the get-go.

Our show begins when tough, young hitchhiker Berkley gets a lift from hunky sociopath Dewey Weber, who generously drives her to Las Vegas, then steals her suitcase (what does he think is inside?). Down-and-out Berkley moves in with dim-bulb waitress Gina Ravera, who remarks, "I haven't gotten laid in six months. My right hand's so tired I can hardly thread a needle!" Soon Berkley's got a gig as a cheesy stripper, but when she gets a look at the Big Time at the hotel Ravera works at, she witnesses a real Vegas show starring Gershon (who, despite the rhinestones glued to her boobs, is indistinguishable from any of the other dancers). A coked-up Gershon turns up at Berkley's strip joint with her hotel boss/lover Kyle MacLachlan, and pays Berkley $500 for a nude lap dance, during which Berkley, in a fit of originality, licks her own nipple. Whereupon Gershon encourages Berkley to audition for the hotel show.

Surveying the line of hopefuls, snide show producer Alan Rachins snarls at the first, "What are these, watermelons? This is a stage, babe, not a patch!" Viewing Berkley's nipples, he leers, "I'm erect, why aren't you?" Berkley is hired and proceeds to witness the dog-eat-dog world of showgirls: one chorine growls at seamstress Ravera, "You're gonna see a smilin' snatch if you don't fix this G-string." Well, maybe it's more dog-eat-dog-food: over lunch Gershon tells Berkley, "I've had dog food. I used to love Doggie Chow," and Berkley gushes, "I used to love Doggie Chow, too!" The brief bonding over pet food experiences ends when Gershon plays with Berkley's breasts, cooing, "You are a whore," and Berkley rejects her, sneering, "Bitch!"

Berkley is visited in her new, "classier" digs by her old strip-club pals, one of whom thinks Berkley "looks better than a 10-inch dick," and the other of whom comments, "Must be weird not having anybody come on you." Flush with success, Berkley goes after druggy McLachlan. Naked in his pool, she sits on him and does a whiplash-like imitation of sex which resembles nothing so much as an epileptic fit. (You'll want to add some Tide and throw in your laundry!) Then, having stolen Gershon's guy, she shoves Gershon down a staircase, and that night she takes Gershon's place in the show and becomes a star (although she, like Gershon, blends right into the chorus). Her triumph is spoiled when pal Ravera is gang-raped by a rock star and his friends. Suddenly, Showgirls veers off into Cleopatra Jones/Coffy territory, with Berkley becoming a martial-arts super-heroine -- Ninja Showgirl? -- who kicks the rocker senseless. After French-kissing Gershon farewell, an older, wiser Berkley blows town, hitching a ride with, yep, luggage thief Weber. The duo heads for L.A.--to work, we hope, for Zalman King in a sexy cable TV series lifted from their roles here: each week, a little lap-dancing, a little crime-fighting. (Well... I'd lap it up).