Just how on Earth does someone go about becoming an opera singer?

“My parents are still asking themselves that!” laughs Marcia Bellamy.

“‘Just how did this happen?’”

The Brighton-based mezzo-soprano couldn’t be further removed from the glacial intensity of operatic stereotype; she’s warm, clever and engaging as she talks about preparing for 18 nights at the Royal Albert Hall in a sumptuous English language version of Madam Butterfly.

“It’s a huge production, and very beautiful. But it’s a very intense experience, because we don’t rehearse for very long, and my character Suzuki never really leaves the stage until the orchestra does at the end.”

When you think that the show’s running time is more than two hours, Bellamy will clock up in excess of 40 hours of stage-time throughout the run. Considering most of us are barely able to utter a croak after a tipsy turn on the karaoke, you’d think it would take an enormous amount of effort to keep the voice in check for more than a fortnight, yet Bellamy says it’s relatively simple.

“I try to avoid too much coffee as we go into rehearsals, but it’s really just about trying to rest,” she explains.

“With the commute on top of family life with three children, rest is a minor obsession of mine!”

Bellamy has performed at the Albert Hall some 30 times, yet its Italianate dome seemed rather a long way off when she was growing up in the picturesque, yet sparsely populated Palouse region in Idaho, US. She got her first glimpse into the world of opera and musical theatre through public broadcast radio.

“I grew up listening to this programme every afternoon called Fourth Row Centre – ‘For people with a song in their hearts and music in their souls’. I’d never been in a theatre, so I had no idea what fourth row centre was … I thought it was an actual centre that people went to!”

The misunderstanding had been put firmly to rest by the time Bellamy completed her training in Seattle; her childhood piano teacher had spotted her talent and intelligence as a singer and fixed her up with a tutor who helped her to explore her potential. On graduating from an MA, she toured the Midwest and Canada in shows before securing a scholarship that would send her to work on the bottom rung at the prestigious Deutsche Oper Berlin (which, as you may well have guessed, is in Germany).

“It was a very steep learning curve, but I was very lucky because I’d done a year’s exchange in Germany at High School, so I had the language.”

She honed her technique over eight years with the company, and was in Berlin when the wall – symbol of a Europe rent in two for close to three decades – came down.

“We actually ended up watching it on telly with the rest of the world,”

she laughs.

“But the great thing was the atmosphere the next morning. A good friend of mine owned a curiosity shop and had lost his father in the war, and when I went to see him, he was just sitting in his shop crying.

He was so happy because he felt his city had been restored to him. There were so many moving scenes like that.”

Bellamy has lived “in lots of wonderful places” before and since, but she’s keen to point out the transient nature of being a performer isn’t all about luxurious Continental travel.

“Anybody who goes into something like this must be prepared for that aspect of it,” she says.

“I’ve been lucky in having eight years of continuity in Berlin, but I’ve donea lot of moving back and forth.”

It was with one foot in London and another in Innsbruck, Austria, that Bellamy met her husband, writer and playwright Stephen Plaice (whose Brighton connections run deep – he wrote the acclaimed play Trunks, based on the city’s trunk murders).

“He was at a workshop, teaching people who were writing librettos, and I was there to sing them as they were being composed.”

Roll forward to today, and Bellamy considers herself fortunate to have a husband who understands an industry that demands unusual hours and long stints away from home.

“It does make a difference. Strangely, when offers come up, it’s more likely to be me who’ll say: ‘Oh gosh, it’s going to be too complicated to organise the childcare and everything’, but he’ll always say I should go for it.”

The couple share their home with three children, an upright piano, and a small selection of guitars.

“To my great delight, they’re all interested in music,” she says of her children. “But we have no intention of encouraging them to be professional musicians – you have to let them do what they want to do. But the good thing about living in Brighton is that there are so many social opportunities to be had with music here.”

Bellamy has been in Brighton for 12 years now, and loves being close to the capital “but still in a place that very much has its own character”. When she’s not on-stage, she teaches singing in every kind of musical discipline – something she’s kept up for many years.

“I’ve always loved doing it. I really do find myself learning all the time and it’s just completely thrilling to share in somebody else’s development – and hopefully saving them from making the mistakes I made the hard way.”

The different strands of Bellamy’s work converge in her role of conductor of the choir at The Church Of The Annunciation in Washington Street, Brighton.

“It’s actually the church where we were married,” she says.

“They found themselves rather abruptly without a music director, and it’s been a great opportunity for me because I’ve done some composing for them as well.”

As well as its regular Sunday singing masses, the choir has performed at Chichester Cathedral for evensong.

Between this, motherhood, her teaching and composing, it’s remarkable that Bellamy is able to squeeze in 18 nights in South Kensington.

“Suzuki is one of my favourite characters and this really is a show worth seeing,” she says, allowing a brief giggle to escape.

“And that’s not something I’ve been able to say about every show I’ve been in!”