Shades of Silicon Valley

As the wife of Silicon Valley tech billionaire Elon Musk, British actress Talulah Riley largely gave up her career to support him, and be stepmother to his five sons from his first marriage.

Their on-off, off-on relationship saw them marry in 2010, split in 2012, remarry 18 months later - and they are now in the throes of divorce again, although the 30-year-old actress, who starred in the 2005 film Pride & Prejudice and St. Trinian's, insists it's all amicable.

"We are best friends. We do see each other and talk nearly every day. We'd been together on and off for eight years, so we're family. I don't want to say why we're not together, it's private. Marriage is difficult but I do love him."

Hertfordshire-born Riley met 45-year-old Musk - co-founder of PayPal, CEO of the Tesla electric car firm and the entrepreneur behind SpaceX rockets - at a London nightclub. Within weeks, she'd moved to LA to live with him and his five young sons, of whom he shares custody with first wife Justine Musk.

They travelled in private jets, held elaborate parties, attended Obama's inauguration and enjoyed a romantic zero-gravity flight over California.

Today, Riley's life is very different. She's single and lives alone in a four-bedroom house in Brentwood, California, with her dogs, border collie Timmy and Labrador Roscoe. Her favourite hobby is hiking in the Santa Monica mountains, although she manages to fit in the occasional round of golf too, in between writing.

"My life tends to be dogs and books," she says. "I don't really go out a lot. LA is a strange town in that it's spread out, there's no real centre, and I have a handful of close friends who I love and adore here, but other than that, most of my friends are in England."

She says her experience with Musk hasn't put her off marriage ("It probably looks mad from the outside but it hasn't put either of us off marriage. We are both very romantic people"), or the idea of having children of her own ("I love children. I love my stepchildren, I would love biological children. I'm a maternal person").

Right now though, she's focused on launching her career as an author.

Her newly-released debut novel, Acts Of Love, centres on Bernadette, a hard-nosed female journalist who wiles the men she interviews. She has her sights on one particular man, but is wooed by Radley, a charming Silicon Valley billionaire.

So, is the story based on her own relationship?

"Not at all," Riley insists. "But in classic literary romance, there's always that power disparity between the male and female characters. Who are the landed gentry of our day? It seems to be Silicon Valley CEOs. A lot of the book is very tongue in cheek."

After reading Fifty Shades Of Grey she decided to transpose the stereotypical misogynist, making the female character the dominant party.

"In a lot of romance literature, the male characters have characteristics which would be considered quite misogynistic, like [Jane Eyre's] Mr Rochester. Yet those guys are considered really attractive to women.

"What if there was a female character that was equally obnoxious, sexually manipulative, conniving and out for herself? That was the genesis of the book.

"I wanted her to be incredibly good-looking and incredibly successful, like a female Christian Grey, to change the standard dynamic."

She may have created a strong anti-heroine, but her own acting career virtually stopped when she met Musk and moved to the US.

"My acting career was only when I was in England. I acted from the age of 18 to 22, then I left very abruptly to come to America, which halted things. I shifted my priorities on to other things. I had a young family."

An only child, to senior policeman-turned-screenwriter Doug Milburn and businesswoman Una Riley, her comfortable childhood began in Hertfordshire's Hemel Hempstead, attending Haberdashers' Aske's School for Girls and Cheltenham Ladies' College.

Her parents also enrolled her into Saturday morning acting classes in London's Sylvia Young Theatre School, though she never went to drama school full-time. She clinched the role of Mary Bennet in Pride & Prejudice the day after finishing her A-levels, after appearing in a small role in Poirot while still at school (they were looking for unknowns to play Keira Knightley's sisters, the other sister was played by Carey Mulligan).

"Acting enabled me to inhabit some of the books I loved, like Pride & Prejudice and Poirot and Marple. It was exciting to think I could properly pretend [to be] in these books," she recalls.

Acting also helped her overcome chronic shyness and the panic attacks which have dogged her since she was a teenager - though she says she never gets panic attacks on set.

"It's not related to anything except existential dread, and it could happen any time, anywhere. The first time it happens, you feel like you're dying," she explains. "But once your body's been through it a few times, you realise it's just something you have to sit out.

"It can be a tight pain in the chest and dizziness. For a long time, a trigger was flying, and I couldn't get on a plane."

She sought help from a hypnotherapist, and credits her dad too.

"I'm getting a lot better at managing them, with help from my dad. I'm much better at controlling them now. I'll remove myself and go and lie down with my legs up and do deep breathing."

Riley is currently working on her second novel, a political thriller set in the near future, and is now appearing in the HBO series Westworld as an 'anti-robot'.

She would like to resume her acting career, but feels she would be better placed to so in the UK.

"I miss the UK," she admits. "I've lived here eight years. My parents moved over here [to the US] a couple of years after I did, so I'm OK on the family front, but I miss my old school friends and the city itself. I miss the culture, the theatre, museums, the food and the English countryside.

"I would consider moving back," she adds. "But I still have some obligations here..."

• Acts Of Love by Talulah Riley is published by Hodder & Stoughton, priced £12.99. Available now