La Fille Du Regiment, Royal Opera House, London <!-- none onestar twostar threestar fourstar -->

Things have come on a little in the 40 years since Joan Sutherland and Luciano Pavarotti strutted their ample stuff in the last Royal Opera staging of Donizetti's Frenchified charmer.

In another 40 years someone will be talking about the night their successors - Natalie Dessay and Juan Diego Florez - showed everyone how the piece should really be done. It's hard to imagine how this adorable, pint-sized, pairing could ever be bettered. But the same goes for the entire cast - as good as you could now muster from anywhere on the planet.

Drop them all into a production from Laurent Pelly that needs no special pleading on comedic grounds, and is by turns elegant, witty, and laugh-out-loud funny, and you've one of the happiest nights the Royal Opera has fielded since I don't know when.

A gentle yodel from a solo horn sets the Alpine scene. The designer, Chantal Thomas, has a map of the Tyrol quite literally strewn across the stage, crumpled sections of it marking out mountainous peaks. The French are on the offensive (in every sense) and the makeshift barricades on view are elaborate enough to send Trevor Nunn back to the drawing board with Les Misérables.

Enter the "daughter of the regiment", Marie - the sensational Natalie Dessay - who is a cross between Annie Oakley and Calamity Jane, only French. She's one of the lads, foul-mouthed and butch enough to tote a rifle but feminine enough to be ironing their undershirts or peeling their potatoes - and all the while tossing off Donizetti's wicked coloratura like it, too, is all in a day's work.

The real joy of Dessay's performance (and it's one of the best all-round operatic performances I've ever seen) is that the singing is always a true extension of the characterisation. The pyrotechnics are timed with such perfection, like verbal exclamations, that there isn't a note, a roulade, a top E-flat, that doesn't get a laugh. Being French she can play with the dialogue, too, and when she is reflective she is vulnerable and touching. Her excellent voice blooms pleasingly in repose, and her tender farewell at the close of act one could not be lovelier.

The local boy Tonio - Juan Diego Florez in lederhosen - is from the wrong side of the barricades. Of course, everyone is waiting for the succession of high Cs in his first-act clincher, and Florez pops them like shrugs of his elegant shoulders, bringing the house down in the process. The naturally high tessitura of his voice makes it all sound utterly effortless. We know better. But what makes Florez special, the tenore di grazia of his generation, are not the high notes, but the exquisitely fluid line, the way in which he is always seeking out and finessing the next elegant turn in the phrasing. When he pleads for Marie at the close of the show, it is the artistry and the grace of it that stops you in your tracks.

And that's the perfect outcome for a romance which begins with Marie offering Tonio a flower. As she does so a sepia postcard descends from above inscribed "Baromètre de l'Amour". It is just one witty aside in a production which abounds in them.

Laurent Pelly blocks the evening to perfection, making something hugely vibrant of his excellent male chorus and even creating (with the choreographer, Laura Scozzi) a tiny, chuckle-making, ballet for the parlour maids.

As I say, none of this would be possible without a truly stellar cast. Two marvellous character actor/singers - Alessandro Corbelli and our own Felicity Palmer - ensure that the comedy is well-anchored. And there's a third to give Palmer's indomitable Marquise de Berkenfeld a run for her money. Dawn French (as La Duchesse de Crackentorp) ditches the Dibley vicar's cassock for an appropriately mountainous frock and, in a ludicrous mix of bad French and colloquial English, gets her priorities right: "Sweetheart, don't be stingy with the chocolate fountains."

To 1 Feb (020-7304 4000; www.royalopera.org)