MOVIES about movies can be dangerous vanities. (Hey! We're filmmakers! Making films within films! What amazing lives we filmmakers lead!)

Diane Kurys' "A Man in Love" dives headlong into that genre and surfaces soaked with pretentiousness. Behind the scenes of an Italian movie set, an American actor is having an extramarital fling with a starlet. And Kurys probes this affair mercilessly, like some Jacques Cousteau in search of Greta Scacchi's dorsals.

Scacchi is the starlet Jane Steiner and Peter Coyote the American star. And there's the flub. Both actors, moderately watchable in other films, are out of place here. Coyote's Steve Elliott, a self-possessed American actor, has decided to star in an international production in Italy about Italian poet Cesare Pavese (or, as his agent complains, about an obscure Italian communist). But Elliott appears to be remarkably untalented. He interprets Pavese as Rocky Balboa and is given to on-set prima-donnybrooks. That Pavese film is doomed for a worldwide pan.

Scacchi's Steiner is similarly underwhelming. Both on and off the set, she's clearly uncomfortable -- resting on looks, clunky acting and a whiny Brit accent. Did Kurys (a Frenchwoman directing in English for the first time) intend for both characters to be such mediocre actors? Hard to tell. Hard to care.

Kurys plays up le-film-wizzina-film angle by having Coyote and Scacchi play a scene, then pulling back to reveal they are acting in the Pavese film. This meta-movie stuff, Elliott's narcissism and the offscreen affair give "Man" more than passing similarity to Franc ois Truffaut's "Day for Night" and Fellini's "8 1/2." But Kurys' efforts come off as forced versions of those films -- structure-for-structure's sake.

And, as was the problem in her 1983 film "Entre Nous," Kurys' attitude to characters is at cross-purposes with the audience's. Elliott and Steiner are brats seeking gratification at anyone's expense. He makes his personal assistant keep his wife in the dark and Steiner leaves her French boyfriend dangling. They also ignore their responsibilities to the film and production crew. And the more Kurys widens the story (we meet Steiner's parents and her boyfriend, as well as Elliott's wife), the less it clarifies.

Claudia Cardinale is warm and radiant as Steiner's dying mother and Jamie Lee Curtis turns in a respectable performance as Elliott's estranged, petulant wife. But they work around the edges of a film that sags in the middle.

A MAN IN LOVE (R) --

At the West End.