For seven years, the Duchess of Kent, a qualified music teacher, has been teaching at primary school. For the first time she has spoken about her work to the BBC One programme, Real Story, the first interview she has given since dropping her HRH title two years ago.
"Call me Katharine" were her first words. It took a bit of getting used to I must admit.
And after her initial shyness had passed, she was always warm, friendly and chatty. But what struck me above all was just how "normal she is.
Yes, she's related to the Queen, has a house in the grounds of Kensington Palace and the kind of roster of charities you associate with royalty.
But she also uses public transport, goes to the supermarket, knows who's in the Top Ten and shops at Zara.
At a very youthful-looking 65, she is doing what she considers to be the most meaningful part of her working life, which she has never spoken about until now.
For seven years, the Duchess, a qualified music teacher, has taught at a primary school in Hull, East Yorkshire. She had never revealed its location until last week.
"Now stand tall and waver your hands about. Waggle them really fast like this, as if you've got a piece of Sellotape stuck to your fingers and you want to shake it off.
A class of 20 nine-year-olds frantically wave their hands in the air as if their lives depend on it, giggling and following the energetic movements of their teacher.
The Duchess is wearing a black waistcoat and trousers, with trendy black-and-white trainers, that elicit admiring glances from the children.
"I absolutely love it. I think more and more that it is the most important thing I do. And primary children are like little sponges.
Music for all
They really want to learn, so teaching them is very satisfying. It's a privilege. To me it's one of the most exciting jobs anyone can do."
Her experience has shown her how music has something to offer all children, how it can help them thrive, even those from the most deprived backgrounds.
It is the reason she has overcome her instinctive reticence and agreed to be interviewed.
She feels strongly that music is being overlooked in schools to the detriment of our children's future.
"It gives them dreams and aspirations. It's a wonderful cross-curricular activity and I can't think of a subject in the school curriculum that music doesn't cover. History, geography, arithmetic, command of English - every song is a poem.
"I'm sure you'll find that when children do Sats, because they're taught to stand tall when they're singing and performing, they walk into their tests with greater confidence."
Watching Katherine with a class - her first time with this particular group of children from John Betts school in Hammersmith, West London - it is clear she is in her element.
Her natural shyness and lack of confidence disappear. She takes control, she laughs with the children, she's affectionate and caring with them. But there's no question who's in charge.
One girl confided later: "I think she was a really good teacher, but she wasn't how I expected - I expected her to look more Royal and wear a crown and look a little bit like the Queen."
Another admitted: "I thought she was going to be more posh and bossy.
Katharine is tickled by the fact that her trendy trainers attracted more attention than anything. "They were far more interested in my trainers", quite frankly.
There's all this lovely thing about them enjoying the music and I ask them to listen to this and try that, but at the end of it all they come up and whisper: 'Miss, liked yer trainers'."
She gives a loud belly laugh, showing a side that she never allows the public to see.
"One of the lovely things about teaching children is you do laugh with them so much. They come out with such lovely comments and such intelligent comments too. If as a teacher, you don't have a sense of humour you won't get anywhere."
The Duchess is a trustee for the charity Youth Music
I'd read articles which described her as lonely and depressed, spurning public life for spinsterish solitude. She does not deny that the headlines wound her but insists they are inaccurate.
"No, I'm not a recluse. If I were, then I'd have to be a very busy one. And depressive? Aren't we all? We all get slightly low periods in our lives, don't we?"
"I think that is allowed quite frankly. I'm far too busy. Teaching is a full time job. I travel to Manchester, I travel to Aldeburgh. I travel to and from London on a regular basis for various things. And I look after my family. I cook for my husband."
This glamorous grandmother shakes her head at me, pushes back her trademark thick ash-blonde hair and adds: "I wish I had more time, frankly. Don't we all?"
Real Story: BBC One, Monday 15 March at 1930 GMT and live on the Real Story website.