Once upon a time - last summer to be exact - Eva Cassidy saved Jane Green's life. If it weren't for a CD present of the late Fields of Gold singer, the author might never have discovered the malignant melanoma on her leg, which was spreading.

"It was May 31 - a friend of mine had given me her CD for my birthday," recalls US-based Green, 47. "When I played it, I thought how have I never heard of this incredible singer, so I Googled her and found she had died of melanoma. That night, I was lying in bed, and my eyes fell upon a tiny little mole, and there was something that didn't look right.

"It had a black splodge in the middle of it. I looked at it and I knew."

Green, meeting me over coffee to discuss her new book, Summer Secrets, went to see her dermatologist immediately, who confirmed her fears.

"I love her, and we have quite a jovial, jokey relationship. When she looked at my melanoma, her face went very serious. And then she phoned 12 days later - I was on a train coming back from New York, and she said, 'Do you have time to talk? It's cancer'."

Within days of the diagnosis, Green had turned herself into "one of the world's leading experts", says the mum of four, with a laugh. "Part of how I deal with things is by informing myself. I need to know everything about everything."

But what came with that knowledge were frightening statistics: "I knew that if it was in my lymph nodes, the numbers were not quite as good."

She's a self-confessed lifelong sun worshipper ("I blistered my way all over the Mediterranean") and says melanomas diagnosed today are from sun burn in childhood and adolescence. But there's also a genetic element, as her uncle died from malignant melanoma.

Luckily for Green, the cancer was caught early before it had spread to her lymph nodes.

"I'm cancer free, but every three months, I have to go for full body checks and when I get back [to the US], I'm going for X-rays.

"I never expected to be dealing with skin cancer, so that was a bit of a shock."

It was the latest in a recent string of health problems the author has faced over the last four years, starting with a tick bite in 2011 that gave her Lyme disease.

"I'm a gardener, so I remember pulling ticks off, but I never had a rash and I never thought that I'd get sick. My neurologist explained it to me as, 'You live on the East Coast of America, you cannot avoid being bitten'. We have such a problem with deer and they're deer ticks."

Undiagnosed for months, the disease sparked a massive autoimmune response, giving Green terrible migraines and extraordinary exhaustion: "There were days when I couldn't walk up the stairs. I'd take one step and then collapse on the steps crying."

She also has Hashimoto's disease, where your immune system attacks your thyroid gland and you gain weight, suffers neuropathy ("The nerve endings went in my hands and my feet. My party trick is I can pick up anything") and Raynaud's syndrome, affecting her circulation.

"I'm extraordinarily strong and I don't really know any other way to be. I just plough through," she says of coping with life's storms.

Green managed her symptoms by cutting out dairy and carbs for a year, and had never felt better.

Hardest of all was giving up sugar - she admits she's addicted (aren't we all?) - and during that year, she started going to alcoholics anonymous, although she wasn't really an alcoholic.

"I'm not a very good drinker, I'm a lightweight. The most I can have is two drinks. But I had given up alcohol because I was trying to recover from exhaustion.

"I'd been around 12-step programmes for a long time, and the only requirement for membership is the desire to stop drinking, so I started going to meetings.

"I have that addictive, compulsive personality, alcohol just happens not to be my drug of choice, but I really do understand it, because I have that gene.

"Every walk of life is represented in those rooms. There's this fear and it allows us to think that we couldn't possibly be [alcoholic] because we're not rolling around, drunk in the street. But actually, it's just drinking more than other people..."

At the meetings, she found "tremendous wisdom", some close friends - and the inspiration for her latest novel.

Summer Secrets centres on Cat, who we first meet as a hard-drinking twenty-something journalist in London. She learns from her American mum that her father wasn't her real father and in fact, he's still alive and an artist living in Nantucket. So Cat flies to meet him and her two half-sisters, but ends up alienating her new-found family when her drinking gets out of control.

Green says the story of a discovered family was actually that of her husband's cousin, who in his 50s learned he had a father and brothers he knew nothing about.

"He had this tremendous sense of coming home and has continued to have an extraordinary relationship with his brothers."

Although Green was also a journalist, she certainly never drank herself into a stupor and woke up with dim memories of the night before, as Cat does.

"I'm not very good at not being in control," she says.

She published her first novel, Straight Talking, at 27, married an American and moved across the pond at 32. She had four children, went through a divorce, married again in 2009 after a chance encounter with the landlord of a holiday cottage and is now happily settled on the Connecticut coast with her "blended family" of six kids.

"Frankly, most of the time I'm just treading water, trying to keep my head above," she says of motherhood. "You muddle through. I'm very strict on manners. But with technology, I feel like I'm fighting a losing battle. Life is so busy and even with the best intentions in the world, I just do the best I can."

She has a little office at the Westport Country Playhouse, where she goes to write each morning, while the children are at school, and is grateful for having her own space and identity.

"I live in a town that's an hour outside of New York where most of the men work, and their wives don't, because it's a status symbol to not work. And these are smart women; they have wonderful degrees from the best universities in the country.

"I've always felt so lucky that I have the perfect job. I get to work and I'm defined by something other than being someone's mum or someone's wife. I have something that's entirely mine, and I also get to be a full-time mother."

While life in America is "easy", she misses the British sense of humour and that Brits "don't take themselves too seriously".

Refreshingly, in a culture obsessed with body image, she makes a stand by not hitting the gym ("On principle, I refuse"), and she's branching out with a cookbook - Good Taste - and has a furniture line in the offing.

Her 18th fiction book is starting to take shape in her head too, even if she's not sure whether the 'chick lit' tag still fits.

"I'm proud of having been at the forefront of this huge genre in fiction, but that was almost 20 years ago, so I don't think I'm writing chick lit any more; it feels young. I'm 47 and I defy anyone to call me a chick these days!"

And with that, she drains her Americano and heads off to meet her school friend and chick-lit contemporary, Freya North.

:: Summer Secrets by Jane Green is published in hardback by Macmillan, priced £12.99. Available now