A tannoy announcement for “Lady Macbeth” causes momentary alarm on Anna Netrebko's face... but it's a rehearsal call for Shostakovich's Lady Macbeth of Mtsensk rather than the role of Verdi's Lady which she's currently performing at the Royal Opera House. Netrebko's here with her husband, Yusif Eyvazov, who sings the tenor role of Macduff, and they're clearly making the most of being in the capital. Netrebko was tempted to try on the Crown Jewels on a visit to the Tower of London. She could certainly justify her case, having played Anne Boleyn in Donizetti's operatic take on Tudor history. The couple's exploits are widely self-chronicled on social media – “It's more Anna than me. I'm lazier!” quips Yusif – with a glorious photo of Anna sporting deerstalker and pipe at the Sherlock Holmes Museum which is clocking up likes by the thousand on her Instagram account. “My life is amazing because of all the travelling I do, so I just share what I see.”

Elementary, my dear Anna!
© Anna Netrebko

Netrebko made her debut at the ROH 18 years ago. She giggles when I show her the Audrey Hepburn-like photo of her playing Natasha in War and Peace, emblazoned across the cover of the Kirov Opera's 2000 residency. “My God,” she sighs, “I loved that role, one of my favourites. The production was quite crazy – 300 people on a revolving stage!”

For Eyvazov, her husband of two years, Macduff marks his Royal Opera debut and, having read the first reviews, he is glowing. He's fully conscious of the significance. “It's a very important step in my career,” he acknowledges. “The Royal Opera House is a big name to have on your CV. When I first rehearsed on stage, it seemed so small compared with the Bolshoi or the Metropolitan, but it’s a huge honour to be here.” It's Eyvazov's first time working with Sir Antonio Pappano and he's full of praise for the House's Music Director. “He has an incredible humanity – you don’t often find this in conductors. His musicality and his love for singers make me really happy.”

Yusif Eyvazov (Macduff)
© ROH | Bill Cooper

In her early career, Netrebko sang a lot of the lighter, soubrette roles – Adina, Norina, Zerlina – before her voice darkened and grew larger, allowing her to venture into heavier repertoire which has seen her triumph as Lady Macbeth, Leonora, Aida and Manon Lescaut. I wondered just how much those “-ina” roles really appealed to her, but she remains positive. “They were wonderful for my voice. When you’re young, you have to perform these kind of roles, with lots of acting, lots of movement, but after a few years I felt it was time to change and luckily my voice allowed me to do that. It was a big decision to move to heavier repertoire. You know, I think I could still perform Adina easily. I can pull my voice back, but I just don’t see any reason why I’d want to sing her any more.” Violetta is another role to which she's said farewell. “I don’t have any more Violettas. For what? I did this one at La Scala last year because I wanted to do a big, old-fashioned production.” She concedes she can still sing it, but asks me “Violetta at 50? No!” She’s younger, but I take her point.

In a moment of reflection, Netrebko admits “I know that the roles I’m singing now are shortening my vocal career. They are demanding and they ruin your body, your soul, your voice, everything. Each performance takes so much from you, so there’s a slower recovery time, but these roles are worth it, I guess!”

Anna Netrebko and Yusif Eyvazov
© Kirk Edwards

In 2014, after years playing Massenet's coquettish Manon, she moved onto Puccini's version, a role she describes as “a killer”. It was during rehearsals in Rome that she met Eyvazov. What were his first impressions of Netrebko? “That she was a crazy prima donna! How could she sing Adina in January and then come to Rome and learn Manon Lescaut?!” “I didn't know the role!” interjects Netrebko, laughing. “But I was very impressed by her professionalism,” he continues. “It was the first time I had worked with a big star... even if Maestro Muti wanted to be the bigger star in that situation. In the end, Anna stole the show, even from him!”

There's clearly little love in the room for Riccardo Muti, who also conducted them both – although in separate casts – in Aida at last year's Salzburg Festival. But his wife, Cristina, is acknowledged as an important influence on his career. “She is a lovely person. She gave me my first big break when I sang Otello in Ravenna.”

For her part, Netrebko connected with Eyvazov straight away, even if it wasn't “love at first sight”, both being beyond the age for such a thing. “I understood his voice immediately. It was clear what he could be. He needed more experience of singing and being on the stage, but he had all those high notes, and his voice already had a very special timbre. He’s worked very hard in the years since and has made amazing progress.”

Željko Lučić (Macbeth) and Anna Netrebko (Lady Macbeth)
© ROH | Bill Cooper

I first saw Netrebko’s Lady Macbeth at the Metropolitan Opera in 2014, a remarkable, high velocity account boasting a voluptuous new chest register. Her Leonora (Trovatore) and Tatyana in Paris were equally luscious and now it's London's turn to experience “Trebs” in full throttle powerhouse mode. “I was born to sing this role!” she laughs. “It takes a lot of power and stamina but somehow it’s comfortable for me. You just need to be strong.”

At Covent Garden, as at the Met, she is joined by Željko Lučić as Macbeth, “one of the few baritones who can actually sing it!”. Eyvazov sings Macduff, a minor role but, the Azerbaijani tenor points out, one that lots of young tenors take on. He admits he's more of a verismo than a Verdi tenor – he braved the Milanese loggionisti to open the La Scala season in the title role in Andrea Chénier, which is no mean feat in itself – but has Radamès in his sights. He also tackles Don Alvaro in La forza del destino at the ROH next season. “I’m forty now, the perfect age to take on anything you want. I’m sure my voice is not working 100% how I want it to work, but I will find new things in the next few years.”

Anna Netrebko (Maddalena) and Yusif Eyvazov (Andrea Chénier)
© Brescia/Amisano | Teatro alla Scala

In that Forza, Netrebko makes her debut as Leonora, a role she freely admits she wouldn't have considered if it wasn't for Pappano's persuasive powers. How does she approach learning new roles? “I’m all for the old school of singing,” she explains seriously. “It’s about good breath control for every single note.” She listens to recordings: Mirella Freni, Maria Callas and especially Renata Tebaldi: “the way she phrases and sings so correctly really helped me when I was learning Aida. One false step and you’re out!” She listens out for phrasing, for musicality. “I listen how different conductors take the score. Studying from the greatest is very important. To study with the piano is not the thing. Only when you sing it several times on stage with the orchestra does the role come to you and you understand it.”

It would be fascinating to hear the pair in Russian repertoire. Eyvazov has just sung his first Pique Dame at the Bolshoi – “my new favourite role” – and he includes Herman's aria in their Royal Albert Hall gala on 23rd May. Netrebko sings Marfa's aria from Rimsky-Korsakov's The Tsar's Bride, a beautiful solo, but I muse whether she'll ever sing Lisa in Pique Dame. “It's a slightly heavy role, on the spinto side,” she complains, but hints that with the right production and a good conductor, she could be persuaded. I tempt her with tales of Stefan Herheim's staging which comes to Covent Garden next season. But will we ever see her Tatyana in London? She's quick to dismiss Kasper Holten’s ROH staging of Onegin. “I would sing it here, but you have a bad production so I’m not coming! Tatyana? Any time. In five, seven years, I’ll still be able to sing her, so if they change the production, I’ll be here with pleasure!”

Peter Mattei (Onegin) and Anna Netrebko (Tatyana)
© Guergana Damianova | Opéra National de Paris

The RAH gala also includes duets from Andrea Chénier, Otello and Tosca. Desdemona isn't a role that interests Netrebko though. “It's beautiful, but it's not me,” she confides, before Eyvazov cuts in to say “You wouldn't be able to find a tenor who wants to kill her!” which earns him an affectionate kiss on the shoulder. Netrebko screws up her nose when I mention Tosca, another role she had said she would never sing but, after Macbeth, she heads to New York to make her role debut in Sir David McVicar's production. So what changed? “Because everyone asked me to sing it!” she sighs. “I will learn how to love her. There are very few possibilities of not making Tosca seem ridiculous. Everything I see in productions disappoints me. But the music is incredible... it’s like a movie.”

The pair have sung a number of gala concerts together (“our voices fit well together in duets”) but although they're often scheduled to sing in the same house, or even the same production – Tosca at the Staatsoper Berlin, for example – they don't always sing in the same performances. “We cannot sing together all the time, it would get boring!” guffaws Netrebko, before Eyvazov explains that they accept – or reject – what the intendants offer, rather than angle for joint appearances.

Anna Netrebko (Tosca)
© Ken Howard | Met Opera

Talk of new roles prompts me to ask my usual question to tenors: If you woke up as a baritone for the day, which role would you sing? Eyvazov answers instantly. “Grigory Gryaznoy in The Tsar's Bride. It contains beautiful music for the baritone.”

Netrebko cuts in. “I would sing Scarpia!” she declares, a devilish glint in her eyes. Perhaps she’s found her motivation for Tosca after all.