What we forget about Darcey Bussell is that she is, first and foremost, a prima ballerina.

“Yes people I know reasonably well, will often come up and say ' I had no idea you were so good'.” she sighs.

Retired now from The Royal Ballet, where she became the principal dancer at just 20 years old, she joined the ranks of the greats, her swanlike English-rose countenance, elegance, poise and grace thrusting her into a global spotlight which she coasted with ease.

But a ballerina’s life is a short one, and when children and marriage beckoned, Darcey stepped down after 20 years at the top of her game, handing the mantel onto the next prodigy.

An yet her name has never diminished, her reputation still revered, and thanks to Strictly Come Dancing, of which she is the only female judge, she is now better known than ever.

And yet, while she talks about Strictly with great respect, and obviously enjoys the prime time BBC dance show, it’s only when you mention ballet that Darcey truly comes alive.

For example, she is much more animated when telling me about her new dance programme for schools, or the fact that live ballet is now being screened in cinemas, ringing me specifically after the interview to make sure I passed this on, than she is about the Strictly.

But then when you’ve been training all day, every day, since you could walk, presumably that determination and commitment continued long after she hung up her ballet shoes?

“I don’t think anyone who has watched Black Swan will doubt that,” she laughs. “So I’m much better when I’m working or have a project to work towards.”

Which may be why she has finally released a book; Darcey Bussell: A Life in Pictures, of her favourite personal ballet memories, which she is airing at the Blenheim Literary Festival.

“It difficult for my girls having a mother in the public eye and I am very conscious of that.

“So I wanted to have something for them to reflect on for, something they can see, to show them the most important part of my working life, because it can all be forgotten so quickly. So it is my story told through pictures, but nothing overly scandalous,” she chuckles.

With so many memories and highlights to choose from that must have been hard to whittle down? “It took a while to compile and sieve through them all yes.”

And yet Darcey then managed to totally reinvent herself for a primetime Saturday night slot on the BBC.

“I never thought I would get so much work when I retired nine years ago. I did not appreciate that it would go that way. As an ex dancer, I expected dancing to be my career in a coaching, teaching, patronage, working in schools. I never thought it would go this far.

“But then I’ve always been a yes person, so when Strictly came up I went for it, even though I’ve gone in at the end, and I really enjoy it.

Quite a far cry from ballet though? “Strictly has changed people’s perceptions of dance, that it’s something everyone can do, that it’s about enjoyment as much as it is about skill. It has certainly brought ballroom back into fashion and it’s been great to be part of it because it’s such a positive family show.

"They have made Strictly into something really special and all the judges bring something different to the table. But at the end of the day it’s about entertainment.”

It must be nice to dress up as well? “I’m used to that, so getting ready for Strictly just feels like putting on a different costume. If I didn’t make the effort I wouldn’t feel as if I was in the right space.”

Still managing to fit in teaching – “I really enjoy the fitness dance programme in schools and training up the coaches. It’s so important. It’s got a bit of everything from all genres and eras and so much fun to do."

She has also just done a documentary on Margot Fontaine for the BBC, continuing her series on Darcey’s Ballet Heroines, is president of the Royal Academy of Dance and works with numerous dance companies and charities around the world, gaining a well earned CBE in the process. "I’m having a great time working my butt off and enjoying every minute of it,” she chuckles again.

Pleased to be returning to Oxfordshire, where she got married, as well as being given a doctorate by Oxford University, to appear the Blenheim Literary Festival, I ask her one final question: So what advice would she give to any young ballerinas?

“That it has to come from you, not from your parents or teachers. Yes it is a famously cut throat industry but it’s theatrical and dramatic. I was very much of the mindset that I wouldn’t waste my energy on that sort of thing, that it wasn’t worth it, so I just let it go on around me. I did not immerse myself in it like others did, but immersed myself in studying my craft instead.”

And I think in that one very English statement she says it all really; how she got there, how she stayed there, and how she will remain there. Inspirational stuff.

Darcey Bussell talks to Paul Blezard: An Audience with Darcey Bussell, Thursday October 13, Blenheim Palace as part of the Blenheim Palace Literary Festival which runs from October 13-16. blenheimpalaceliteraryfestival.com