Co-written by Marc Norman (Cutthroat Island) and Tom Stoppard (Rosencranz and Guildenstern Are Dead, Brazil) -- who, on this evidence, doesn't work in films often enough -- the script moves quickly, making it a pleasure just to keep up. Here's a movie that revels in the old-fashioned task of creating rapid-fire dialogue that cracks wise even as it reveals character. And when the movie takes a breather, as it often does, to wallow in Shakespeare's original dialogue, the results are suitably magical. No, we don't need this movie to tell us that Will Shakespeare sure could turn a phrase, but the reverence is appropriate in a film that doubles as a valentine to the theater. All the cliches are accounted for, from the size of actors' egos to the intricacies and absurdities of billing. Summing up the tastes of the mass audience, one character remarks, "Love, and a bit with a dog -- that's what they want." (Notably, this movie has both.)

Joseph Fiennes plays a handsome, credibly intense Shakespeare who's struggling with a new play as the film opens. Under pressure from beleagured theater owner Philip Henslowe (Geoffrey Rush) and producer Hugh Fennyman (Tom Wilkinson), he's having a devil of a time getting a grip on his newest comedy, which he's titled Romeo and Ethel, the Pirate's Daughter. The film has an angst-ridden Will trotting uneasily around Elizabethan London, taking mental notes on overheard fragments of dialogue, bantering with rival playwright Christopher Marlowe (a dashing Rupert Everett), and putting off his deadlines in hopes of encountering his muse.

As the title suggests, he finds it in the form of a beautiful woman at Queen Elizabeth's court, Lady Viola (Gwyneth Paltrow). Will is advised to forget about her -- not only is she a member of the upper class, far beyond the reach of a mere playwright, but she's already betrothed to the boorish Lord Wessex (Colin Firth), who plans to carry her away to his plantation in Virginia. However, Viola is so taken by Will's performance for Her Majesty that she steals into the theater disguised as a boy, for women were not allowed on stage. There, she auditions for the part of Romeo before a clueless Shakespeare.

That you can imagine much of what happens next is unimportant -- yes, the two of them fall in love, and yes, Will draws on his passion for Viola to create a lushly romantic Romeo and Juliet, and yes, it's the impossibility of their love that gives his newly retitled play its tragic bite. In the film's lushly realized centerpiece love scene, Viola's breasts are unbound and Will finds the meaning that has so far eluded him. What matters is that it's all executed with humor, smarts, and an unobtrusive stylishness that catches you up in the storytelling, from the sharp, densely colored widescreen cinematography to the surprisingly deft choreography of a show-stopping swordfight. Judging by the roars of laughter from the preview audience, Miramax and Universal have a serious crowd-pleaser on their hands.

The casting is shrewd, with a rich ensemble helping us revel in the melodrama that saturates the film. Fiennes' boyishness worked to his disadvantage in Elizabeth, where he seemed too thinly drawn for the political intrigue of that picture. Here, it's an impetuous virtue, with Fiennes' Shakespeare sweeping the entire company up -- even the prima donna Ned Alleyn (Ben Affleck), playing Mercutio -- in the enthusiasm surrounding his tragic yarn.

The film is similarly flattering to Paltrow. In both Great Expectations and Sliding Doors, she was photographed in a way that drew attention to her rail-thin limbs and dressed-by-Gucci good looks. Here, she's less specific and far more ravishing. Her performance seems tentative in spots (and who could believe that Gwyneth in a goatee could ever be mistaken for a boy, even in Elizabethan garb?), but she does nail the Shakespeare. This is likely to emerge as the star vehicle that has eluded her since 1996's Emma.

Judi Dench, meanwhile, may now finally have her fill of playing royalty, having anchored Madden's previous film, Mrs. Brown, as Queen Victoria. She brings clarity and credibility to the key role of Queen Elizabeth, who presides, Solomon-like, over Shakespeare in Love's England. Indeed, it's her responsibility to carry the film's key closing passage, a twisty and turny sequence that spells out the destinies of the young lovers before her. She exudes a sort of stern generosity of spirit, but one that won't permit a bending of her own authority. Rush, Affleck, and especially Wilkinson create similarly lucid characters who lurk around the edges of the main romantic action.

Altogether, Shakespeare in Love operates at a level of wit and invention that more naturalistic contemporary pictures can rarely afford. This should, after all, be the great triumph of a period piece -- an attention to grace and literacy that would strike an errant chord in modern Hollywood. Smart, cute, mooningly expressive and swooningly romantic, this splendidly entertaining flight of fancy is the kind of movie that gives romantic comedies -- even period pieces -- a good name.