Magdalena Kozena's motherly love

Her new CD has a maternal theme – just right for Magdalena Kozena's new role as a family woman

With her dazzling looks, Magdalena Kozena is surely one of the most glamorous women on the operatic stage. That's even before she opens her mouth. And when she does – well, you can't argue with that voice. Yet traditionally, it's the sopranos who enjoy the most glitzy operatic roles, with the image to match; Kozena is a mezzo-soprano, a "fach" (voice type) that composers all too often relegate to the roles of sisters, young boys and mothers-in-law. "Of course, if I were a dramatic soprano there would be some wonderful roles to sing and I'm a bit jealous," the Czech singer, 35, admits. "But one should be happy with what one's got." In her case, that's not bad: Kozena, who gives a recital in the Barbican's Great Performers series this weekend, has got everything.

Four years ago, though, she hit the headlines in another way when it emerged that she and the conductor Sir Simon Rattle were leaving their respective spouses to set up home together. Now, though, scandal has subsided into domestic bliss. The pair have settled just outside Berlin (Rattle is the chief conductor and artistic director of the Berlin Philharmonic), and have two sons, Jonas, aged three and a half, and Milos, four months. And Kozena, happy with the quieter schedule she has adopted for the sake of her family, seems as warm as her voice, relaxed and ready to laugh.

Those high spirits illuminate much of the repertoire she's bringing to the Barbican, which also features in her new album: Czech songs from Dvorak and Janacek to Petr Eben, entitled Songs My Mother Taught Me. The music also contains a gentle but deep vein of pathos. "Some of these songs are very witty yet sad at the same time," she says. "The melancholy is very Slavic – we have some heartbreaking melodies."

Motherhood has made a difference, physically as well as emotionally. "Going through those hormonal changes, the voice becomes a bit richer, rounder maybe, and stronger too," she says. "It's not been as great difference for me as it can be for others, though. Some women go through huge changes after giving birth, they even change their fach. Unfortunately," she jokes, "this didn't happen to me. I thought that maybe when I had kids I'd become a dramatic soprano! But no..."

There's no doubt as to who the most important conductor in Kozena's life is. "Some people don't like to work with their spouses," she remarks. "They prefer to separate professional from personal life. But I think that if you know someone so well, then working with them becomes even easier because you don't have to discuss things: you just have this knowledge of the person and their music-making and things happen naturally. It's easier than working with anyone else." Rattle has also led her towards repertoire she had hesitated to tackle before. "Simon encouraged me to sing Mahler, and I think that was a good choice. I always wanted to, but I was scared that it wasn't quite the right time. Now I'm singing this repertoire more and more and I feel very happy in it."

Magdalena Kozena sings at the Barbican, London EC2 (020-7638 8891) on 9 November; 'Songs My Mother Taught Me' is out on Deutsche Grammophon