Housesitter has the prefab atmosphere of a lot of recent comedies it's as peppy and synthetic as a detergent commercial yet it takes off from an idea worthy of Preston Sturges. Steve Martin plays Newton Davis (do names like this exist anywhere except in movies about yuppies?), a Boston architect whose girlfriend (Dana Delany) rejects his offer of marriage and along with it the small-town New England dream house he has built for her. Floundering in despair, he meets Gwen (Goldie Hawn), a con artist and compulsive liar. Gwen shuffles false identities with such liquid skill that she seems a bit crazy.
The two hook up for a one-night stand. But then, instead of going her own way, Hawn moves into Martin's still-empty house and proceeds to pass herself off as his new wife, charming her way into the lives of parents, friends, shopkeepers. Martin discovers that being ''married'' may be the ticket to winning back his girlfriend. So he agrees to play along with the charade.
The two now have to keep topping each other, improvising new, ever more outrageous whoppers based on whatever the other one has just said. Before long, their fake-marriage scenario a bogus litany of fights, tender moments, and sheer trivia begins to seem as genuine as the real thing. The movie is built around the nifty notion that lying and romantic love are rooted in the same quality of unfettered imagination.
Housesitter is, or should have been, a Ping-Pong burlesque about the joyous art of verbal gamesmanship. Yet most of the movie just sits there. As the scenes sputtered and fizzled, I kept imagining how terrific the film might have been with, say, William Powell and Myrna Loy, and I wondered why it wasn't better. The easy answer is that Martin and Hawn are no Powell and Loy. The real problem, though, may be that the makers of Housesitter no longer believe in this sort of castle-in-the-air farce.
Beneath their patterned plots and obligatory happy endings, the screwball comedies of the '30s and '40s had a blithe, amoral zing. The characters hammered each other with wisecracks and generally behaved like duplicitous kooks because that's what love made them do. In Housesitter, Hawn and Martin go through the motions of romantic madness, but we never feel their chatter is bubbling up from inside. The strings of lies sound canned, recited. The two seem like screwball automatons.
Martin, like the comics who rocketed to the movies via Saturday Night Live, now seems a performer without any new tricks in his bag. Once again he plays a Totally Normal Guy whose feelings come bursting out in twitchy, mimelike spasms. By now, though, we know his mock-spazalopolis moves as well as we know our own reflections. Martin's coolness the compulsive way he turns emotion into stylized camp hurts him in ''straight'' roles. He doesn't seem to have a romantic bone in his body, and there's an eerie lack of chemistry between the two stars.
Goldie, who's in her low-voiced, womanly mode here, does her best to maintain the energy level. She gets to deliver the movie's best anecdote, a Harlequin Romance-style howler about how Martin never saw her face until their wedding day, when her bandages from an accident were unwrapped.
In general, though, every time Housesitter seems about to turn wild, it gets waterlogged with heart. During a party, Martin has to play along with one of Hawn's fabrications by singing the lullaby ''Too-ra-loo-ra-loo-ral'' to his father (Donald Moffat). The scene should be a gonzo high point: You can just imagine what the Martin of the early '80s would have done with it. Instead, it has been engineered for tears. One of the major differences between Housesitter and the classic comedies it echoes is that the people who made those films understood that you didn't have to wedge ''feelings'' in between the jokes. The jokes said it all. C-