Anna Netrebko/Rolando Villazon, Barbican, London <!-- none onestar twostar threestar fourstar fivestar -->

This season's operatic sweethearts - Anna Netrebko and Rolando Villazon - are still officially just good friends. But the body language says otherwise; either operatic acting has just got a whole lot better or these two exciting talents have lately been exploring "the method". There's chemistry, and there's chemistry.

When Manon came to find her erstwhile lover Des Grieux at the seminary of St-Suplice in the duet "Toi! Vous!", no sets or costumes were necessary to convey the rekindling of a passion. Netrebko, in low-cut black, used her seductive pianissimo like a caress; Villazon's resistance was futile.

Later at this joint recital (and you have to wonder why two such rising stars would not want to go solo?), playful zarzuelas made an art of flirtation, and the climactic scene from Tchaikovsky's Yolanta had its blind heroine and her knight in shining armour seeing the light in thrilling unison.

And, of course, there was Mimi and Rudolfo ("O soave fanciulla") taking that long, slow walk into the moonlight and both going for the top C, though he, the perfect gentleman, held back to allow her the limelight. There was no concealing their glee at this opportunity to show off together. They hugged, kissed, laughed, waved; we were less an audience, more guests at some sort of party.

Netrebko really showed us what she's made of, warming the voice nicely with "Je veux vivre" from Gounod's Romeo et Juliette, exciting the febrile coloratura with real artistry. Notwithstanding an element of steeliness in her tone and occasional lapses in intonation where she pushes emotion to the limit - as in Rachmaninov's stunningly operatic song "Ne poy, krasavitsa" - the intensity of what she does is arresting. Some climaxes suggested that she was at her limit. That's a dangerous sign; we must wait and see.

Villazon is the genuine article. But he had his lapses, such as a hesitant account of Lensky's "Kuda, kuda" from Tchaikovsky's Eugene Onegin. But he wowed us in Sorozabal's "No puede ser!" with a wickedly protracted pay-off and wrung all the emotion from mummy's boy Turiddu's aria "Mamma, quell vino" from Cavalleria rusticana.

There was some indifferent support from the Royal Philharmonic under Emmanuel Villaume, and an ill-advised encore of "Tonight" from West Side Story. Grim. But when you are this young and talented, even the lapses in judgement have their charm.