Smoking with Lulu, Soho Theatre, London

Separated by a generation and a great deal more, Louise Brooks and Kenneth Tynan face each other across her bed. The silent-screen goddess he has dreamt of for so long before their meeting in 1978 – "aristocratic, sophisticated, cosmopolitan" – is now an old woman, the pert bob and beaded dresses replaced by grey hair streaming over the bed jacket of an arthritic recluse.

"Face it," she says, bored with a lifetime of strangers being besotted with her: "this face is 50 years older than the one you had in mind when you were outside my door."

As we have seen the look on Tynan's face, we can hardly believe his denial. But Ken and Louise find another means of communion. As she talks about herself for the New Yorker profile he will write, they breathe each other's smoke and exhale more. Sharing the cigarettes from his silver case, they burn away illusions as they slide nearer the grave (he would die of emphysema in 1980; she would outlive him by five years).

Janet Munsil's short, clever play isn't concerned with the life of the actress or critic but with the nature of glamour, truth and obsession. While Tynan talks with the aged Brooks, and we see excerpts from the film Pandora's Box showing her in her incandescent youth, the young Louise appears, mischievously dancing round the author and offering herself to him.

It is quite a tribute to Sophie Millett to say that, made up and costumed as Lulu, the film's angelic-whore heroine, she doesn't suffer from comparison with the astonishing image behind her. As Louise becomes more real to Tynan, however, Lulu has less of a hold on him. They boldly, then shyly, seek to know more about each other, quarrel and reconcile. He envies her life of sin; she yearns for his world of quality-lit chat.

Such a work stands or falls on the plausibility and charm of the players, and the principals here are not short of either. Thelma Barlow's Louise is salty, lightly sardonic ("I never read anything written about me that didn't make me puke"). From a great beauty who would terrify or astonish men by saying whatever was on her mind, she has become a woman who now merely amuses them by doing the same.

Barlow expertly maintains her composure until the pretence of artlessness becomes too difficult, and the terrified old lady beneath begins to break through. Peter Eyre downplays Tynan's sophistication, showing us the self-doubt of the self-made man, slipping from clever-cleverness into solicitude and surprising himself with a boyish, rabbity chuckle at his idol's more outrageous mots.

David Giles's production is stylish enough to sweep us past any doubts that Tynan, whose vices have recently become rather too well known, is being sentimentalised. There is one exception, though: the off-stage voice is meant to be that of a real 1970s librarian in upstate New York, not a caricature of a Brooklyn telephone operator from the Thirties.

To 30 March (020-7478 0100)