Soprano Danielle de Niese: 'I'm not the first singer to go back to work after having a baby'

De Niese and her husband, the Glyndebourne owner, Gus Christie, are expecting their first child at the end of this month. But that isn't stopping her tackling the lead roles in two Ravel operas at the world-famous festival

Grass act: Soprano Danielle de Niese at Glyndebourne (Sven Arnstein)

Over lunch at Glyndebourne's staff canteen, the soprano Danielle de Niese, who is heavily pregnant, is telling star-studded anecdotes. Recently, en route to a charity gala with her tell-tale bump disguised beneath the drapes of a Vivienne Westwood gown, she changed trains at Clapham Junction. A hand on her arm, an "Excuse me, but…" – and there on the station platform, she declares, was Dame Vivienne Westwood herself: "She spotted her dress first and then said – 'Oh, it's you!'" De Niese giggles.

There's no mistaking the charismatic "Danni" de Niese at the best of times: today she seems positively in overdrive. As her fame has grown, De Niese's supersize personality has grown with it; and at 36, she is firmly established as a consummate artist, in her element in roles that allow her to explore virtuosity as physical as it is vocal. It was in just such a part – Cleopatra in Handel's Giulio Cesare, in David McVicar's award-winning Glyndebourne production – that she shot to fame in 2005. Then, too, she met the country opera house's hereditary proprietor, Gus Christie. Reader, she married him, in 2009. Their first baby is due at the end of May.

The imminent new arrival does not mean that De Niese's career will change track. She is due back on stage as early as 8 August to star in both works of Glyndebourne's double bill of Ravel operas, L'heure espagnole and L'enfant et les sortilèges. In the latter, she plays a small boy punished for his cruelty by the animals and objects around him. And in L'heure espagnole, she is the sexy, seductive clockmaker's wife, rather topically named Concepción.

It sounds like a big ask just two months after giving birth. "I intend on being up for it," De Niese insists. "If life gets in the way – for instance if there was a big pregnancy complication – then obviously the priority is the baby's health and mine. But I have four weeks before rehearsals and eight before the show opens. If I'm in good health, there's no reason I wouldn't be able to go ahead. More than anything else I really want to do it – I was looking forward to it for so long." She has kept her fitness levels up – "I get some funny looks at the gym," she remarks – and her mix of long-ingrained stagecraft, professionalism and sheer tenacity should put plenty of tools at her disposal.

She first sang the Child in L'enfant et les sortilèges in her early twenties, at the Metropolitan Opera, New York. "I went down as one of the youngest people to do a title role in the history of the Met," she says. "Many of my colleagues were surprised that [the conductor] James Levine had cast me in that role as I was so girly and curvaceous. That only spurred me on even more.

"I did a lot of research, visiting daycare centres, observing how kids use their pelvic floor. So much of our body language, between boy and girl or man and woman, is based on our pelvis. In the end my own parents didn't recognise me on stage – though you'd think I'd be easy to spot, as my skin is darker." De Niese's exotic looks stem from her mixed Sri Lankan, Dutch and Scottish roots; she was born in Melbourne, and the family moved to Los Angeles to facilitate her stage training.

It is sheer good luck, she notes, that Glyndebourne is her first engagement after the birth. "I wouldn't have been able to take a three-and-a-half-week old child on a plane to a strange place. Here, I have a five-second commute. Gus and I," she adds, "are going in with a 'we'll find a way' attitude. We're good at multitasking. I already have two careers – as singer and as wife and support to Gus at Glyndebourne; there's the house to run; and of course Gus is already a dad [he has four teenaged sons from his previous marriage]. It's not like we're going straight from being clubbers to being stay-at-home parents."

De Niese nevertheless jettisoned, reluctantly, the title role in Lehár's operetta The Merry Widow at the Met this spring. It wasn't that a pregnant merry widow might have looked incongruous, she insists: "I really wanted to do it, and it was an interesting concept, the idea that one might not be the desirable size for a role – in opera that's not something we think of any more. But I'd have been in my ninth month of pregnancy and having to fly back from New York – and can-can dancing and acrobatic lifts when your waters might break…"

She plans to press on with the leading role in the new opera Bel Canto by Jimmy Lopez, based on Ann Patchett's novel, scheduled for Chicago next season. And her appearance at the Last Night of the Proms in September stays firmly in the diary: "There's no possible way I would give that up unless I was dead!" she declares. That night she sings first in the Proms in the Park, then nips over the road to the Royal Albert Hall to lead a four-nation, hooked-up audience in a mass singalong of The Sound of Music.

Inside the RAH, she will have a very different companion: the German tenor Jonas Kaufmann, whose magnificent voice and matinée-idol looks have made him the operatic superstar de nos jours. She first met him, she says, when she jumped in at late notice to sing Monteverdi's L'incoronazione di Poppea in Zurich with Kaufmann as Nero. The opening scene featured Poppea and Nero under the sheets together, clad in "next to nothing", but they had no chance to meet beforehand. "It was 'Hi, I'm Jonas', 'Hi, I'm Danni', and we had to start making out... But the last duet was really gorgeous."

By September De Niese will have enjoyed an unusually long span of five and a half months at home – and Glyndebourne, a haven of tranquility flanked by the South Downs, is quite a place to call home. Gus Christie's grandfather, John Christie, founded the opera festival at Glyndebourne in 1934. It was the original British country house opera, and arguably remains the most beautiful, offering opera-goers world-class performances, the chance to picnic in the grounds and an excuse to dress up.

Danielle de Niese with her husband, Gus Christie (Sam Stephenson) (Sam Stephenson/Glyndebourne)

This year the gardens boast a brand-new rose garden plus a new, small art gallery that can be erected at the start of each summer and dismantled afterwards. Exhibitions are being organised in collaboration with White Cube; the first features the celebrated German artist Georg Baselitz. Opera-goers may view his series of new paintings focusing on the leg and the foot, with titles referencing musical inspirations.

As for the festival itself, the Ravel double bill – a revival of Laurent Pelly's whimsical, smash-hit production – is set to be a prime attraction. Proceedings open on 21 May with a rare treasure: the UK premiere of Donizetti's Poliuto, directed by Mariame Clément. Two further new productions are Handel's oratorio Saul, staged by Barrie Kosky; and Mozart's Die Entführung aus dem Serail, with David McVicar at the helm. The programme is completed by revivals of McVicar's naturalistic realisation of Bizet's Carmen and Fiona Shaw's powerful take on Britten's The Rape of Lucretia.

First, there'll be the baby. De Niese (who says she has not asked if it is a girl or a boy) is the first to admit that she worries the media may speculate on "whether now Mrs Glyndebourne is going to take precedence over Danielle de Niese and she'll have a couple of kids and go away for five years. Our age loves to put people in little boxes and shut them in…" Potential changes to her voice – which many singers experience due to the physical transformations wrought by pregnancy – are still an unknown quantity, though she feels her sound is growing: "It was having a growth spurt anyway and I think the tone is becoming richer," she says. Still, being no shrinking violet, she currently has a BBC camera crew following her around, developing a show that tracks her progress towards a big new production next year.

"I'm not the first young woman to go back to work after having a baby and I won't be the last," she remarks. "I'm not the first singer to do it either. I'm looking forward to being a mother, but I can also return to my passion with even more passion. I know it sounds like I'm asking for a lot – but if it works, it works, and if it doesn't, it doesn't and I'm not going to sit around crying. In a way, if it all goes well for me, I can do everything."

Glyndebourne Festival Opera (01273 813813) opens on 21 May Danielle de Niese sings in Ravel's 'L'heure espagnole' and 'L'enfant et les sortilèges' from 8 August