A Belfast choir that is about to stage a production of the Sound of Music, has revealed a special link to the real von Trapp family.
Members of St Agnes Choral Society got a shock when one of their own members, a Belfast nun, unveiled herself as a long-time pen pal of Maria von Trapp.
Sister Dympna O'Daly intrigued her fellow singers when she told them she had begun writing to the world's most famous governess about 30 years ago.
But perhaps even more surprising was the fact that Mrs von Trapp wrote back - and Sister Dympna still had the personal letters and pictures to prove it.
The correspondence came to light as a result of a chance remark, as the choir made preparations for their production of the hit musical, which is due to open in Belfast next week.
The singing nun mentioned the letters in passing, as she had coffee with the choral society's vice-chairman, Kevin McKavanagh.
Starting at the very beginning - a very good place to start - Sister Dympna explained that she was working as a teacher in Nigeria in the late 1970s when during one school holiday, she picked up a copy of Mrs von Trapp's 1949 autobiography.
The book, The Story of the Trapp Family Singers, told the story of an Austrian novice nun who was appointed as governess to the children of a grief-stricken widower just before the outbreak of the Second World War.
She encouraged the children to sing together and perform publicly and later became their step-mother, marrying their father, Captain Georg Johannes von Trapp.
The book inspired the Rodgers and Hammerstein Broadway musical, and by 1965 the story had made it to the silver screen, when Julie Andrews was cast as Maria von Trapp in the Oscar-wining film, The Sound of Music.
The Belfast nun, taking time out from her busy school schedule, found she had much in common with Maria von Trapp.
As a member of the Sisters of St. Louis order, she taught at St Louis Secondary School in Ondo, Nigeria.
The school catered for up to 200 pupils, mostly boarders, so she knew what it was like to look after lots of children who did not have much contact with their parents.
Sister Dympna also shared her religious vocation and her love of music.
Fiona Keegan, chair of St Agnes Choral Society, told BBC Radio Ulster: "Having read it and thoroughly enjoyed the book, she decided to write to Maria von Trapp. However, the address she had really just said 'Vermont, USA', so Sister Dympna wasn't sure whether it would ever actually reach its destination.
"But to her amazement a few weeks later, she received a reply from the baroness herself."
Ms Keegan said the nun had originally written to Mrs von Trapp to tell her how much she had enjoyed the book and to tell her about her own missionary work in Nigeria, but then letters began to go back and forth.
She added that a considerable amount of correspondence between the pair built up over the years, and as it continued, the two women developed "quite a warm friendship, talking about their love of music and reading".
"Also, one of Maria's children went on to be a missionary herself, so that was another connection - a very fond connection with Sister Dympna," Ms Keegan said.
Mrs von Trapp's eldest step-daughter, also called Maria, worked in Africa as a missionary, so the Belfast nun's vocation in Nigeria had particular significance for the author, according to Ms Keegan.
A few of the packages that arrived from Vermont - which may or may not have been tied up with string - contained photographs of Maria and her extended family.
One shows the baroness as an elderly woman holding what appears to be a family pet, another shows a gathering of the large von Trapp clan.
The family had fled Nazi-occupied Austria and settled in the USA, where they performed on tour and set up their own musical camp.
Maria von Trapp died in Vermont in 1987 at the age of 82. By the time of her death she had lived in America for about 40 years.
After her missionary work, Sister Dympna returned to Belfast and became involved with her local choir. She had kept the von Trapp family letters safe and brought them home to Northern Ireland.
Ms Keegan said :"Sister Dympna doesn't sing with ourselves in the society but she sings in St Agnes' choir, which is closely linked with the society. We do the musical theatre stuff and she does the church stuff."
The Belfast production of Sound of Music opens at the Grand Opera House on Tuesday, 16 April.