If British audiences hadn't already realised that there was something very special about the American mezzo-soprano Lorraine Hunt Lieberson, then her performance as Irene in the Glyndebourne production of Handel's Theodora in 1996 put them straight. In that role Hunt Lieberson proved that she was one of the finest singers of our time, an artist of unfailing musicality, piercing directness and evenly beautiful tone.

In the Wigmore Hall on Monday, with Julius Drake as the ever attentive pianist, she devoted her recital to Brahms and Schumann, and it was spell-binding. There is no artifice, no affectation and most of all no self-regarding ego about Hunt Lieberson; she is on the platform to communicate. It helps, of course, that she possesses a voice of such haunting beauty - it's extraordinary that she began her musical career as a viola player, then sang as a soprano, before settling down as a mezzo - and that her musicality is so instinctive.

But the way in which she launched her programme, with the first of Brahms' Eight Songs Op 57 still took the breath away. Daumer's winsomely sentimental poems on which the set is based hardly deserve to be given with such devastating commitment, and she brought more uncomplicated passion out of Brahms' settings than one would have thought possible; this was the kind of alchemical performance to bring round even the agnostics who think of Brahms as terminally uptight, and his songs as the final proof of that repression.

Schumann, of course, is another matter, but here Hunt Lieberson revealed even more subtlety, even more perception. She lavished meticulous attention on the little group of Mignon Songs, while each number of Frauenliebe und-leben ran through a whole spectrum of colour and emotional flux. The way in which "Ich kann's nicht fassen" grew from breathless wonder to untrammelled ecstasy was a microcosm of the emotional journey that the whole cycle charts. Magical.

***** Unmissable
**** Recommended
*** Enjoyable
** Mediocre
* Terrible