NINA STEMME comes straight from a rehearsal of the demanding Act II duet from Tristan und Isolde, Wagner​’​s monumental drama of love and death, when we meet at the Royal Opera House. The Swedish soprano is the world‘s reigning Isolde and also Brünnhilde, as she demonstrated at the 2013 Proms in Daniel Barenboim​’​s Berlin Ring cycle.  It​’​s a status she has achieved, not with overnight stardom, but by patient and gradual development of her ­artistry and instrument, and sheer hard work. 

Stemme is 51, the right age for a singer with a decade of Isoldes behind her, and a ­striking-looking woman: not tall, though noticeable when she walks into the room, but with a disarming, wide-open smile.  She lives in her native Stockholm with her stage designer husband, Bengt Gomer, and their three children.  Barely recognisable as the ­vampish Salome who cavorted at last summer​’​s Proms in a ­spangly side-split frock, she comes across as a sensible shoes Wagnerian diva, with a solid grip on her real life. 

She already has three commercial recordings of Isolde to her credit:  the first in the studio (EMI/Warner) with Antonio Pappano​’​s Royal Opera forces; a more recent one live in concert under Marek Janowski in Berlin with her current Tristan, Stephen Gould (Pentatone); and the 2007 revival of Glyndebourne​’​s production on DVD (Opus Arte). 

Stemme was a finalist in the 1993 Cardiff Singer of the World competition and then spent a decade building up to her first Isolde, at Glyndebourne in 2003, to international acclaim.  Had she always envisaged a Wagnerian career? 

So Wagner came later.  “I had early warning signs from ­colleagues going into the big repertoire too soon.  I was afraid of that, so I decided early on I would always be happy with the repertoire I am singing. And I was very happy at that time, singing Puccini, for instance, even some Mozart​,​ the Countess, a good part for me, and Pamina, which I didn​’​t think was really for me. I wasn​’​t sure how to sing it, and my voice started fluttering.  It was not that big, but I don​’​t think I had the right experience.  That​’​s how I see it now, anyway​.​

In any case, to call Stemme a Wagnerian soprano is a mis­nomer, as her engagements reflect.  In May she will sing Puccini​’​s Turandot in a prestigious new staging at La Scala, Milan, under its music director elect, Riccardo Chailly, and she tackles Strauss​’​s Elektra for the first time at the Vienna State Opera in March. These killer roles, arguably the most exacting in the dramatic ­soprano​’​s repertoire, were also specialities of her famous compatriot Birgit Nilsson, another soprano too limitingly described as a Wagnerian. 

“I love to sing music, not just Strauss and Wagner; whatever I have the chance to sing, in fact, that suits my voice.  I​’​m  lucky that now I am more relaxed and take time between performan­ces, so I can do a wider range of parts.  It​’​s my soul food.”

In some ways, I remark, she is an old-fashioned singer, or, at least, has had an old-fashioned, step-by-step career. “Thank you”, she smiles.  “I take that as a compliment.  Although I sang my first Cio-Cio San [Madam Butterfly] in Gothenburg, I didn’t really want to stay in Sweden at that time, so I went to Cologne.”

Stemme based herself there for four seasons, 1995-99, and it was from there she launched, cautiously, her international Wagner career, first with Elisabeth in Tannhäuser, followed by Senta, both in productions by the British director Keith Warner at the Vlaamse Opera in ­Antwerp and Ghent.  It was as Senta in Antwerp that I first saw her on stage, and it was clear, with her big lyric soprano and handsome stage presence, that the bigger hochdramatisch (highly ­dramatic) Wagner roles were within her reach. 

“I arrived in Cologne with one child and left with three! That was a tough time for me, but we had a very good artistic director at that time. She supported us sopranos, and we didn’t  have to sing too much. I also got to sing Italian repertoire, which is ­perhaps not so common for someone who speaks a ­Germanic language.”

I remind her she made her UK debut in an Italian role: Puccini’s Manon Lescaut for English National Opera in 2000. 

Although Stemme has been a rare visitor to Covent Garden, her debut was as Amelia in ­Verid​i’s Un Ballo in Maschera in 2005.   She is delighted to have a second chance to a Christof Loy’s production, which had a rough ride from the public on its opening night in 2009.  “Here at Covent Garden they take a lot of time to prepare a revival, which is good.  A production like this needs time to settle. We have to digest it, talk about it, see it through new eyes. It’​’s a very clea​n production, new, fresh.  We’ve worked on it hard, psychologically, and ­analysed the text to the bone.”