Classical soprano Margaret Keys will never forget the day one of her pupils handed her a piece of paper that would soon change her life forever.
The 35-year-old singing sensation from Londonderry was teaching in a school in her home city at the time.
She is a leading light on the world stage, charming everyone from Rod Stewart to the Pope and members of the royal family with her angelic voice and distinctly warm and humorous style.
Since giving up teaching to follow her musical dream, Margaret has enjoyed enormous success, securing a deal with Universal Records and singing for some very famous names in some of the world's largest concert venues, including New York's Carnegie Hall.
Growing up in Derry with twin sister Rosemary and two other siblings, Tina and William, Margaret was heavily influenced by her grandparents' love of the music of Elvis Presley, The Fureys, Maria Callas and, of course, another local hero, Josef Locke.
Her grandmother was also the winner of the Deanna Durbin singing competition at just 16 years old, so there is definitely something in the genes.
Speaking on the third episode of the new series of Eamonn Mallie: Face To Face With... which is broadcast on UTV tonight, Margaret says the celebrated Irish tenor played a big part in her childhood.
"He was one of the bigger names that my grandfather introduced me to," she says.
"Josef Locke is Derry's first superstar and he is just lauded there. What a wonderful voice he had, and I decided that was the career that I would like to follow.
"There were four kids in our house and both our parents and grandparents had a huge influence over our lives. My grandparents loved music and it was a passion of theirs. That also had a huge impact on my love and passion for music.
"My passion was the films that they watched, the old MGM movies with all the glamorous Hollywood stars.
"It was so romantic and I'm a hopeless romantic myself. Their favourite song was Sweet Sixteen and I sing that today in every concert."
Margaret's dad Bill died suddenly in March 2014 aged 67. He had been a constant support to her as she progressed in her career.
She was also always told by her mum Mary to "go out and get what you want".
Margaret began singing at the age of four at the McCafferty School of Music in Derry. She later attended Thornhill College, where she played the lead in the school productions of Finian's Rainbow and Show Boat.
She shared her Thornhill years with Derry Girls creator Lisa McGee and former Girls Aloud singer Nadine Coyle.
Margaret recalls: "Lisa was so down-to-earth and clearly very talented from a young age.
"We travelled on a bus every day together in school and, looking back, Lisa used to look out the window, so I think she was probably taking in the environment. That can be clearly seen in this wonderful creation she has made for the Derry Girls.
"Nadine was a very talented girl from a young age with a wonderful voice and she deserves every success."
While Margaret admits getting a lot of stick for her love of classical music as a teenager, she was determined to follow her dream.
"I think my voice certainly lends itself to classical music but I have a passion for it as well and it was something that I wanted to be able to sing," she tells Mallie.
"I remember as a child in the record stores I would have gravitated over to the classical side and spent endless hours looking at albums and LPs. I was aware of pop music and that maybe I wasn't following the trends, but I didn't really mind. Of course I got stick but it makes you stronger."
Margaret feels especially blessed to hail from a city of song with a wealth of musical talent including Grammy-winning musician, songwriter and record producer Phil Coulter, and Eurovision Song Contest winner Dana.
"There are endless people coming from Derry and everybody influences everyone," she says.
"I think the main reason why there's so many success stories in Derry is because they see the extraordinary in the ordinary person."
Margaret's musical talents progressed throughout her school years and she was awarded the Trinity College of Music London medal for the best overall performer in music examinations within the UK at the age of 15. While studying for a Bachelor of Music Education at St Mary's University College in Belfast, Margaret continued her vocal studies with Irene Sandford from Holywood in Co Down, a professor of vocal studies at the Royal Irish Academy of Music.
"Irene was the catalyst that allowed me to study at a higher level," she recalls. "I remember her saying to me that if I worked hard she felt I would be good enough to be on the international stage, but it was the self-belief that needed to develop."
After obtaining a First Class Honours degree, Margaret was awarded a scholarship to train for a Master's degree at the prestigious Royal Scottish Academy of Music and Drama in Glasgow.
During her studies at RSAMD, she performed as a soloist at the Rennie Mackintosh Museum, Skibo Castle and opera productions, as well as taking masterclasses with Dame Felicity Lott and Sir Philip Langridge.
After graduating from the RSAMD, Margaret returned to her home city to take up a teaching job at St Eithne's Primary School. She recalls: "I came home to earn money but I knew deep down that I needed to sing, even though I loved teaching."
Margaret combined her role as a primary school teacher with her music career, playing the lead role of Eliza Doolittle in My Fair Lady and as the young singer Katy Tourish in a tour of new Irish play A Miracle In Ballymore.
But she continued to excel musically and would soon make a fairytale entry into showbusiness.
"Little did I know that the decision to come home for that year would ultimately change my life," she adds.
One morning a child in the class Margaret was teaching noticed an advertisement in the Radio Times for BBC talent show How Do You Solve A Problem Like Maria? - to find the lead role for the 2006 West End production of The Sound Of Music.
Margaret remembers the moment clearly: "I think that child saw me as a Julie Andrews or maybe her mum saw me in that light.
"She took the little advertisement from her pencil case and said: 'Miss Keys, we think this is something that you should do'. I said: 'Who is we?' She replied: 'Me and my mum'.
"I looked at the advertisement and thought it was wonderful but I was in a job that was paying me money and asked myself was this really the life that I wanted to go into again.
"I went home and thought about it and talked to my parents.
"It's true that you can teach anywhere in the world but there are only certain opportunities like this that come up once in a blue moon, so I had to go for it.
"I took a career break from teaching and auditioned for the show and the rest is kind of history."
During her time on the show Margaret worked alongside Sir Andrew Lloyd Webber and several top West End coaches. "It was a gruelling process but a real learning curve," she adds.
Out of 6,000 entrants, Margaret made it down to the final cut of 20 and was awarded the BBC Fame Academy Award and New York Artist Award, which allowed her to travel and train with Broadway stars and opera vocal coaches.
Around that time, Margaret also won RTE Radio One's Search For A Musical Star and performed the role of Carrie in the RTE production of Carousel with the RTE Concert Orchestra.
She has gone on to perform as a guest on several TV and radio shows including the BBC Proms and Songs Of Praise with Eamonn Holmes.
Margaret released her highly anticipated album The Gift Of Music in June 2018, which was recorded with the City Of Prague Philharmonic Orchestra and dedicated to her late father.
The record soared straight to the top of the classical album charts, fending off competition from some of the world's most famous classical stars and making her the only Irish artist to accomplish such a feat.
"I worked really hard for it but it's not me that gets me there, it's the people who buy the music," she says. "I can only do so much and perform but you are relying on people to purchase it."
Now moving in celebrity circles, Margaret has worked with everyone from Andrea Bocelli and Anton du Beke to Russell Watson and Alfie Boe, among many others, and performed extensively in Ireland, Britain, North America and Australia.
But there is one man she would still love to perform alongside - the 'King Of Waltz' Andre Rieu.
"I'd love to perform and tour with him. He is a genius and has created something fantastic that speaks to the masses and that's ultimately what I'm trying to do as well," she adds.
"He is a showman and through his music he shows his personality."
Margaret is also an ambassador for children's mental healthy charity Place2B, whose patron is the Duchess of Cambridge.
"I have brought over the first pilot scheme to Northern Ireland and infiltrated it into St Mary's College, where student teachers are learning how to bring mental health awareness to a primary school classroom."
Reflecting on her own positive mental health while working in such a challenging industry, Margaret believes the support of her family has been key.
"Of course times are tough and things are difficult but if I pick up the phone to call my mum and sisters, that's important and it keeps me grounded."
Eamonn Mallie: Face To Face With... is on UTV tonight at 10.45pm