There’s something delightfully gothic about Audrey Niffenegger.

It’s not just her books with their cast of incestuous sisters, timetravelling husbands and ghostly twins; it’s the 49- year-old’s red hair, her pale illustrations; the knowledge that she has a house stuffed with taxidermy animals.

So it comes as no real surprise when she tells me, in that laconic Chicago drawl, that she’d rather like some pet ravens “if I didn’t already have cats”.

Monogamous and intelligent, she reckons the birds are “kind of ideal”. I’m not sure if she means as pets or as marriage material.

She has spent many happy hours admiring the Tower of London’s infamous collection as research for her latest project. The Raven Girl is a fairytale book that’s been turned into a ballet and is set to be transformed into a film – as Niffenegger remarks, “kind of thrilling”.

Through a series of dark etchings, she tells the story of our heroine, born of a postman, who falls in love with a raven and is desperate to swap her human arms and legs for wings.

Is it coincidence that Niffenegger’s characters are often women with a strange affliction that separates them from the “normal” world?

I’m thinking of Clare from Niffenegger’s bestselling debut The Time Traveler’s Wife, but there are others too; the forthcoming Chinchilla Girl, cursed with hypertrichosis; the isolated twins Julia and Valentina from Her Fearful Symmetry.

“I’m very aware that I create outsiders,”

she says. “It’s very much how I see myself. I was one of those children who was just reading all the time…a little weirdo.”

Like Wednesday Addams, I suggest? “I can remember watching The Addams Family as a child and thinking, ‘Oh, I like that house’,”

laughs Niffenegger.

“But Wednesday is smart and has a snappy comeback for everything. I was just quiet… and tall.”

There had been attempts to get Niffenegger’s work adapted for the stage before but this project was different; Niffenegger wrote The Raven Girl especially for The Royal Ballet, whose resident choreographer Wayne McGregor has turned it into a show set to open later this month.

She knew nothing about ballet prior to this – “I’m an opera afficionado” – but appears to have found a kindred spirit in McGregor, another hugely successful outsider.

“I’m not even slightly nervous about seeing the show,” she says. “I’ve so much joy in this project.”

This from the woman who has never watched the film adaption of The Time Traveler’s Wife on the basis that “if I don’t see it, maybe I can believe it’s brilliant”.

Ten years after that novel came out, Niffenegger has been revisiting the characters for a project she’s working on with Zola Books, an American ebook retailer to whom she’s granted the ebook rights in a bid to raise the profile of the social enterprise.

The Alba Fragments reintroduces us to Alba, the daughter of time-travelling Henry and Clare, now she is a grown-up. It’s not a sequel as such – Niffenegger isn’t sure what it is. “That’s why I’ve called it The Alba Fragments; it’s glimpses into her life.”

Published in 2003, The Time Traveler’s Wife was Niffenegger’s first taste of mainstream success. Up until that point, she had enjoyed a cosy existence as an artist and writer in Chicago’s “book-arts ghetto” where she was best known for her visual novels. “I used to call them that because I thought it would annoy the comics people if I said they were graphic novels; instead they got annoyed with me because they thought I was trying to distance myself from them.”

She still enjoys that existence to an extent; she teaches printmaking and book arts at various universities and is a founder of Text 3, an artist and writers’ group which performs and exhibits in Chicago.

It’s just that now she gets advances of $5million for her books – which is fortunate given the writing process takes her anything from five to fourteen years. “I do have a tendency to over-research,”

admits Niffenegger, who spent a year working as a tour guide at London’s Highgate Cemetery in preparation for Her Fearful Symmetry.

“I know a lot more about that cemetery than ever made it into the book – you can quiz me!”

The art world was an obvious draw for the young Niffenegger, whose self-portraits depict her surrounded by hundreds of disembodied eyeballs, or with butterflies for ears. Even as a child she was making tiny books from scrap-paper.

She recently discovered the poet Emily Dickinson had done the same.

“I was in Harvard where they have a lot of her original manuscripts and I found these ghostly little pamphlets.

They were startling.”

Her work continues to be a mixture of text and graphic novels whose macabre style is often compared to that of [cult US author] Edward Gorey.

Personally, her tastes range from Egon Schiele – “His line is so amazing… that demented look he gives people!” – to John Singer Sargent – “a virtuoso with paint”.

She can understand the Gorey references though.

“I’ve always been this way,”

she shrugs of her taste for the gothic. “Even my earliest drawings and poems that my mom kept are Halloweenish.”

She views conventional ideas of “normality” with fascination; marriage comes up frequently in her work, pregnancy too.

“I could certainly make a character who never married or had children and spent all her time in the studio…but that would be my life and no one would care.”

In her books, she identifies more closely with secondary characters like Ingrid, Henry’s girlfriend before he meets Clare, or the dead aunt Elspeth in Her Fearful Symmetry, than the heroines.

“I think many artists and writers feel like outsiders but I can’t say it’s a prerequisite.

I just think you need to be able to observe and to observe you often need to shut up and step back.”

*Audrey Niffenegger will appear at this year’s Charleston Festival to talk about The Raven Girl at 6pm on Wednesday.

For tickets, visit www.charleston.org.uk or call 01273 709709

*The Raven Girl (Abrams Comic Arts, £9.99) is out now