When the Daily Telegraph theatre critic Charles Spencer began his review of this revival of Sunday in the Park with George, he dismissed Sondheim fans as a gang of weird saddos. He ended it as a paid-up member. Wyndham's Theatre flutters with the five-star notices universally bestowed on this truly enchanting and stimulating piece, which simply can't be recommended too highly. It's about' the composition of Georges Seurat's huge depiction of Paris bourgeois leisure, Sunday afternoon at La Grande Jatte, where a mixed collection of ages, genders, occupations and pre-occupations promenade elegantly by the Seine.

Much more than that, it's about' the solitude and selfishness of the dedicated unrecognised artist, alienated and alienating in society, conscious always of having something new and important to say, and in a new technique. We focus on George (Daniel Evans) and his long-suffering model/mistress Dot (Jenna Russell), but wily Sondheim makes magic use of every modern device lighting, graphics, film, multiple images video and no doubt others unknown to me to evoke movement, change, creation itself.

George describes his art in two numbers, Colour and Light and the unforgettable Finishing the Hat (all the women have hats, of course, but Dot's is the hat), while the milling Sunday crowd including the dogs is moulded into eternity as we see the finished painting take shape.

That's it, then. Oh no. Here Sondheim and his writer James Lapine play one of their little tricks (remember Into the Woods?). We move several generations on, to America where great-grandson George and his grandmother Marie (Dot's tiny baby) are at a reception. Old George's colour and light have become a 'Chromolume', a flashy light and laser show that busts the electrics cue house-lights up and the techies rushing on.

Here art is politics. Putting it Together is the most staggering piece of staging, as light and film effects let us see George working the room handshake here, drinkie there, quick word and exchange of cards with rival gallery owners. Too materialistic? There follows a lovely quiet scene with gran Jenna Russell more moving and exquisitely observed to my mind even than as Dot a return to Paris and a full company celebration of Sunday.

'Company' is the word, as so often with Sondheim. Naughty children, dashing guardsmen, servants gossiping, snooty critics, smooth dealers, all done to perfection. And those hats . . .

Two of Seurat's masterpieces are in London Bathers at the National Gallery, Woman Powdering Herself (which we can also see acted out onstage) at Somerset House. They're permanent. The show isn't, so don't miss it. (Box office: 0870 950 0925 ).