13/04/2011 11:30 BST | Updated 22/05/2015 06:12 BST

Tatiana De Rosnay: The Best-Selling Writer You've Probably Never Heard Of

Photo: Philippe Matsas

Appropriately for someone about to release a book entitled A Secret Kept, Tatiana de Rosnay is perhaps Europe's best kept literary secret. We get the feeling she won't be staying a secret for long though - her book Sarah's Key has been turned into a film starring Kristin Scott Thomas and sales of her books in Europe are only eclipsed by those of Dan Brown and Stieg Larsson. We met up with the novelist to enjoy a cup of tea and find out more about her books, her extraordinary heritage, and her love of social media. (And if you're planning on reading her book, don't worry - we requested no spoilers!)

Can you tell us a bit about A Secret Kept?
"This book is about a family secret and how a man deals with it. He will come to terms with an unsettling truth concerning his mother who passed away quite a while ago. It's also a book about mid life crisis; I wanted to explore that from a male point of view. That was something new for me as a writer. So a man stuck in the grip of a very unsettling mid-life crisis. He's sandwiched between his life as a divorced lonely dad bringing up his teenage kids, his aging father who is not the most agreeable man in the world and some very unhappy love affairs he's had online after his wife has left him for a younger man. He will have to force himself to snap into who he really is as a man, a dad, a brother, a son, an ex-husband. He will have to come into his own."

The first chapter of A Secret Kept really hooks you in – is that the most difficult part to get right?
"I find that - and this goes for my tastes as a reader, not only as a writer - I love being hooked into a book immediately. The opening lines of a book are so important. You really need to somehow charm your reader. If you can't get her attention in the first pages you may have lost her. There has to be an ambience. Not necessarily the entire cast of characters but something that is planted into the reader's mind so she'll say 'What's going to happen?'"

Was it hard writing from a male perspective?
"It wasn't the first time I'd done it but it was the first time I did it with such honesty and lucidity. Previously I'd written a couple of novels where men were heroes but I did it tongue in cheek, making fun of men in not a very nice way but I was a lot younger in those days. Now, as I'm approaching 50, I probably know a lot more about men than I used to. I think Antoine comes out as a very realistic character. Most of my readers think he really does exist and I've modelled him after somebody but he's an imaginary figure. My next book – the one I'm going to write this summer - will have a male hero."

Is that the ultimate compliment, when someone assumes the characters are real?
"Yes. I get very touching emails from my male readers who say thank you for writing this book and you've recognised something – you obviously know men quite well."

As someone who is truly bilingual do you ever find it hard to write completely in one language?
"It's a complicated process being so bilingual. Sometimes it's a mere word or sentence that comes to me, if I'm writing the book in English, in French. It's not always easy to deal with. Sometimes even during an interview somebody can ask me a question in English that I want to answer in French and vice versa – that's the story of my life!"

What was it like having your book Sarah's Key turned into a film?
"They consulted us a lot. Gilles Paquet-Brenner was very keen on making sure I would know all about the different stages of the script and I was also included in the promotion of the movie. I'm used to promoting books but a movie is a very different thing. You have to go to film festivals and wear fancy clothes and try and look glamorous and intelligent when you're just terrified and you want to go home! But I was so excited by the whole story I didn't have to say 'No, I don't like this'. When they said it was going to be Kristin Scott Thomas I nearly died, I was so excited. Maybe it's a bad example because everything went so well."

Was it enjoyable or stressful?
"It was a wonderful experience. Kristin Scott Thomas plays Julia Jarmond and my family and friends all play in the movie – you'll see us very fleetingly. You might not even pick me out – I'm in a restaurant scene. I loved it. Actually, A Secret Kept is becoming a film too – the rights have just been sold to a young French film writer. I'm intrigued to see who's going to be playing Antoine Rey and Angèle Rouvatier. That's going to be a French movie whereas this is a Franco-English movie in that Kristin Scott Thomas speaks English to various people in the movie."

You're very active on Facebook and Twitter – is that vital to success nowadays?
"I was active on social media before I was a successful author. Don't forget that before Sarah's Key I sold 2000 copies of each of my books in a good year. I had a blog at that point, I was already on Facebook. I wasn't on Twitter yet because that's only 3 years old. I've always been a geek so I've always used the internet. Perhaps at first for autopromotion, as many authors do. Now I don't really need that anymore but it's a fantastic way to talk to my readers and let them know what I'm doing. I find it very useful.

"I completely understand that some writers don't like it and shy away from that kind of thing but look at Joanne Harris. I met her on Twitter and have always adored her work. I met her through Twitter and we're giving a talk together here in London next month. She actually tweets such funny things, she cracks me up! I sometimes don't have time to be so witty in my tyweets. I tweet a lot about what I'm doing and where I am or if I'm unhappy or happy about something but I would never put anything personal. I've learnt that."

And you sometimes have Facebook interactions with your characters?
"It was my husband's idea to create Angele Rouvatier's Facebook page and that was a huge success. Shes's such a powerful woman: she'a mortician; she drives a Harley Davidson; she smokes Marlboros – it was so easy to create her Facebook page – she belongs to the Marlboro group, the Harley Davidson group, she lives in the Vendée. We had no idea it would be such a success. The press really picked up on that in France. Then, to my surprise, I started getting friendship demands from character from my books! These are fans creating Facebook pages and completely respecting the code of each character. I find that a wonderful mark of sympathy for my books and what I do for them. It's a fun way of making the characters live on."

Are you tempted to incorporate these Facebook interactions into your writing?
"Yes. In my next novel – the book I haven't started to write yet – it will be about a young male writer, I'm not going to tell you any more but and there will be quite a bit about the social networks an how we writers use them and the pitfalls. Sometimes disturbed people contact you and there are things you need to learn how to avoid as a writer. My young writer will make a couple of mistakes."

Your Twitter biography describes you as Franco-British with a zest of Russian - do you identify with one more than the others?
"I'm such a melting pot. My name comes from my Russian grandmother. She fled the Russian revolution and she was an incredible character. She was the most ungrandmotherly grandmother you can imagine but such a fantastic optimist. I really miss her. It sounds corny to say you miss your grandmother but I really miss her.

"The problem with being such a mix of nationalities is you don't feel you're one in particular. I was born in France but I don't really feel French. Technically I'm half English, and I was raised in America. I'd say I feel a little bit of everything."

You've got such an amazing family tree - have you considered writing your memoirs?
(Tatiana is the great-great-granddaughter of Isambard Kingdom Brunel, granddaughter of Lord Jebb - Churchill's right hand man and painter Gaëtan de Rosnay, daughter of scientist Joël de Rosnay...)

"For the moment, no. I'm really into fiction and I don't think I could write anything else but Isombard Kingdom Brunel who is my great great great grandfather is unknown in France for some obscure reason. One of my plans would be to write about him. It would have to be a novel because there are so many books that exist here about him, after all he's a famous figure of this country – the only novelty I could give would be to track down the French connection. He is franglais like me – his father was French and his mother was British like me. I'm very interested in what he did and his life so one day something might come out of there but I'm not sure. It's circling round in my head but I have to really pinpoint it and work on it."

Who do you curl up and read in the evening?
"I read a lot of French and English writers but there are two writers that I really enjoy reading – one of them is Tracy Chevalier. I met her quite recently. I really enjoy her work. And my absolute British idol is Ian McEwan. Once I saw him fleetingly in a book fare in Oslo and I nearly died! I didn't muster up the courage to go up and speak with him but I was given the pen that he signed with all afternoon and I still have it which goes to show how warped I am where he's concerned! I think he's brilliant."

A Secret Kept is published on 15 April by Pan Macmillan - you can read the gripping first chapter here on MyDaily!