First performed in 1894, Massenet's Thaïs is one of opera's most striking examinations of the relationship between religion and sensuality, and a love story of unique strangeness. In 4th-century Alexandria, the monk Athanaël determines to save the soul of the prostitute Thaïs, only to find his faith undermined by desire as she comes ever closer to sainthood. The opera's detractors tend to regard it as an art nouveau period piece, though it has much to say about prurience and fanaticism, and about the sometimes fine line between spiritual and sensual experience. The score is extraordinarily beautiful, whether depicting religious austerities or the erotic dangers of a great city.

Revivals are rare, largely because of the immense difficulties, vocal and dramatic, of the title role. They were more than met, however, in this concert performance by Canadian soprano Erin Wall. Her glamour is magnetic: you understand why, at the start, men are prepared to bankrupt themselves for Thaïs. More important, however, is the extraordinary ease and sumptuousness of her tone, and a hovering, ecstatic quality in her singing that makes her so convincing as both sexual icon and saint.

There were inequalities elsewhere. Quinn Kelsey's warm-sounding Athanël was curiously uninvolved for far too much of it, though Eric Cutler was immensely appealing as Thaïs's roguish client Nicias. Andrew Davis conducted the Royal Scottish National Orchestra, gradually warming to the score after a slowish start, but eventually achieving a passionate grandeur that swept you away. Ultimately, though, this was Wall's night. I hesitate to write "a star is born" after a single hearing, but she will unquestionably become one if she carries on like this.