As the days go by, Stanwyck starts to let slip her ignorance of her supposed husband. There, Barbara Stanwyck, escaping her lover, tried on the engagement ring of a young woman travelling on the same train to meet her in-laws for the first time. The train crashes and when Stanwyck comes round, she is in bed surrounded by the woman's in-laws, who assume Stanwyck to be their daughter-in-law (who, in fact, died with their son, in the crash). The exposition is slipshod too, as when Pullman mistakenly thinks that Bullock is having an affair with the Italian neighbour, and so gives her a test to check that she really knew his brother. Why would an act of infidelity lead him to suspect her identity to be false?Pullman's ham-fisted inquisition, like the film as a whole, dimly echoes Mitchell Leisen's 1950 classic No Man of Her Own. When Bullock saves Gallagher from the train, she mugs and jokes, and rolls over with him three times, as if in a cartoon And yet later we're supposed to share her angst. Characters, such as Bullock's amusingly lecherous, fat Italian neighbour, flit in and out.

Neither the writers, Daniel G Sullivan and Fredric Lebow, nor the director, Jon Turteltaub, seem sure whether the film is taking place in the real world or in fantasy land. Even the shameless, grand-standing one-liners and tear-jerking finales of Nora Ephron would be preferable to the sketchiness of While You Were Sleeping. They are all stymied by the script, which lacks both wit and heart. Her male co-stars hold the film together: the under-rated Pullman, who can goof without slipping out of character; and the always magnetically malicious Gallagher, who spends too much time comatose for the film's good. But at times it is as if the film itself is a jape for her: she seems to be laughing outside it, instead of in character. Her warmth is infectious, but I find it more winning in her television interviews. Her merriment lends weight to those who argue that film acting is largely a matter of personality.

She is great at a sort of coy embarrassment, averting her eyes and laughing breathlessly, as if trying to suppress her mirth or nerves. And besides, she's fallen in love with his brother (Bill Pullman). Bullock captures well the spinster's dowdy existence (which may be a double-edged compliment), while Gallagher's large, squabbling family brings out the best in her. Circumstances, too complicated and contrived to explain, prevent her from revealing what has really happened or extricating herself from the bosom of her "fiance's" family. When he is mugged and falls on the track, she saves his life.

A mix-up at the hospital leads to her being mistaken for the fiancee of the injured man (who has been left in a coma). Bullock plays an employee of the Chicago Transit Authority, a lonely single woman, who every day fantasises about the handsome yuppie (Peter Gallagher) who buys his train ticket from her. She is not exactly the girl next door - but an idealised version of her, with sparkling teeth and undentable self-confidence. Even her name sounds unstarry (Anna Mae Bullock wasn't showbiz enough for Tina Turner) But the hype, and $8m a movie, tells us she's a star.

Her first leading role may tempt you to say: Bullocks to that While You Were Sleeping is a wafer-thin romantic comedy. Bullock's features have a cartoonish exaggeration: generous nose, brimming lips, and a smile so wide it stretches her face into a gargoyle of glee. THIS YEAR'S model isn't a model-type at all. Sandra Bullock, star of While You Were Sleeping (PG), and Hollywood flavour of the month ("the new Julia Roberts"), is the most unlikely sex symbol since Barbra Streisand. My parents advised me that I should to buy a two-bedroomed one and get a friend to move in to help pay the mortgage, but no way. My friends are, without exception, delightful, but I know that even the most wonderful, kind, good- natured people can turn out to be flatmates from hell.. Admittedly, I was careless to leave hairpins in my shirt pockets when I used Nicole's new Zanussi washer-dryer, which broke the machine.