Love Is My Sin, Rose Theatre, Kingston

"With this key, Shakespeare unlocked his heart," declared Wordsworth of the Sonnets.

To which Robert Browning, preferring to interpret them as dramatic monologues, riposted: "If so, the less Shakespeare he." Peter Brook can evidently see the force of both points of view. In the programme, he refers to the poems as the author's "private diary", but in this jewel of a show he has arranged 31 of them into a kind of playlet for two actors who move through a journey of separation, jealousy and reaffirmation in a sequence framed by meditations on time.

I had worried beforehand that it might come over as faintly ridiculous – like watching a highbrow couple conduct a tiff by firing lengthy quotations at one another. Nor was I convinced that repositioning poems regardless of their conjectured addressee (beautiful male youth, Dark Lady) could be made to work. My misgivings quickly evaporated. Michael Pennington and Natasha Parry deliver the verse with such a spontaneous-sounding feel for its intellectual and emotional intricacies that you end up thinking that nothing could be more natural than conversation by sonnet.

They proceed from mild interaction in the first section on "Devouring Time", to a movingly complete collaborative rendering of Sonnet 116 "Let not the marriage of true minds admit impediment" with which the piece comes to defiant close. As the actors expertly negotiate the nuanced knottiness of the pain, self-disgust and recrimination of the middle poems here, there's eloquent dramatic interplay not just between the sonnets but sometimes within them. Each detail is beautifully judged – the light intimations that both these figures are writers; the 55-minute length; and the musical interludes in which Couperin is performed by Franck Krawczyk on harpsichord and accordion, reinforcing the sense that the formally elaborate and the informal can be fused. A gem that deserves a longer run in Britain.