She ends up looking locked into many of the getups. The pink suit she wears in the opening scene is particularly bad--the collar too high, the hat too big: she could be the incredible shrinking woman in the first stages of diminution. Plus, throughout the movie her fake eyelashes are so thick you can't always see the whites of her eyes. (When McGregor plucks an eyelash off her cheek so she can make a wish, you wish he'd kept plucking, by the fistful.) As a result, the orangey foundation she's wearing makes her teeth look unnaturally white. She looks like a misprinted character in the Sunday funnies.

Am I just being bitchy? No, because the movie sells itself as an exercise in style. (It does, at any rate, represent an improvement over director Peyton Reed's previous movie, Bring It On (2000), a travesty of high school cheerleading that untwists itself for an embarrassingly p.c. conclusion.) To be fair, I don't know if any young female star has the kind of couture-chameleon style the movie is going after (Gwyneth Paltrow can wear clothes, but hasn't figured out how to open up on screen) and I'd as soon watch Zellweger get it wrong as anyone else. (Mira Sorvino can morph into highly stylized characters, as in Mighty Aphrodite (1995) and Romy and Michele's High School Reunion (1997), but those girls were dopes. She wasn't so impressive in Clare Peploe's slightly too fluid adaptation of Marivaux's Triumph of Love (2002), in which she needed to create a character out of a command of theatrical space, and in which she looked swamped in her royal duds.)

At times Zellweger seems to stare out at us, as if waiting for help to arrive. If there was a means by which this actress, with her intense way of pushing past doubts, could have played a woman who falls into doubt from a perch of certitude, she doesn't find it. But stick around for the music video played during the credits in which, singing and dancing with McGregor, she shows the reserves of energy and style the movie fails to call on.

McGregor does much better, moving effortlessly among his roles as a skirtchasing Scottish magazine writer, the shy Southern astronaut the writer impersonates in order to trick Zellweger, and the magazine writer in love (though the switch to the last is the weakest link in the script). McGregor puts an extra facetious twinkle on everything (in the manner of Peter O'Toole in What's New Pussycat (1965)), so that the writer's fatuousness and the astronaut's earnestness don't attach to him as a performer. Yet he never comes across as a celebrity guest star, or acts too cute, or disrupts the movie to let us know he's too cool for it. He uses his talent for self-conscious sketch acting to both heighten and hollow out the role he's playing. This means that the character doesn't really linger in our heads--the movie is too thin for that--but McGregor as comedian and star does. His performance is rococo in the expertise it applies to frivolity.