LONDON — What better way to start of week of theater in London than with a surprising, dazzling Shakespeare at the National Theatre?  Twelfth Night, one of the most frequently performed of his comedies, turns shockingly, persuasively tragic in this brilliant and sly production directed by Simon Godwin. Even more astonishing, given this grave turn, it's hilarious. Laugh-out-loud hilarious.  Minor characters become major, men become women, women become men, the buttoned-up unbutton, and the play is made new, which is to say that this "new" Twelfth Night was always there in the text.

Here's the National Theatre's trailer for Twelfth Night:

All of this reinvigoration rests on Malvolio, the character whose scenes I generally dread as creepy and painful. Usually we are encouraged to mock Malvolio (whose very name means "ill will"), the dour scold of Olivia's household, while Sir Toby Belch and Sir Andrew Aguecheek treat him cruelly. But now, Malvolia (not a typo: This production bends every gender available), played by Tamsin Greig with superb subtlety and geniused timing, snatches the play and makes it her sad and bitter own. After all, if, as Feste's final song tells us, "the rain it raineth every day," life isn't so damned comical after all.

And this excellent, edgy Feste is also played by a woman (Doon Mackichan).  After all, when the play was performed originally, all the roles were played by men, some disguised as women, a fact that had to have grown more complicated when, for instance, Viola disguises herself as Cesario, obliging the male actor playing her to take on a layer of faux maleness, become a man acting a woman acting a man. And then Olivia falls in love with "him." And her brother, Sebastian, thought lost at sea, returns, and Duke Orsino, suitor to Olivia, falls for … well you get the idea. All is eventually revealed and happily sorted out with the main characters in reunions and weddings: the comedic solution.

The casting problem is usually to find two actors to play the twins. They should look enough alike to confuse us (and the production's contemporary dress helps with this — one young person with short hair in jeans and a loose shirt and boots looks much like another).  The costuming throughout misses no chance to comment wittily on the characters and on the tension between then and now. Olivia (Phoebe Fox) wears stilettos with her mourning dress, and her ladies, all in short black dresses and heels, wear little Elizabethan ruffs. Orsino (Oliver Chris), being very straight, woos Olivia with persuasive desperation. At his own birthday party, he wears a button saying "Big 40," but in a moment of confusion he gives Sebastian a big smooch. Antonio, the rough, tough ship's captain, wears a getup that hovers somewhere between a kilt and a dress.  The two mischief-making drunks, Sir Toby and Sir Andrew, wear sleazy and significantly outmoded clothes.

Soutra Gilmour, the production's designer, provides not only the delightful costumes and hairdos, but also the nifty revolving set — and several tiny, amusing moments are made of its revolving.  As Feste (the wisdom always comes from the Fool) comments, "Nothing that is so, is so." Certainly not on stage.