Nell Zink was 50 when she made the leap from secret writer to published author - and she blames it all on the award-winning writer Jonathan Franzen, her unlikely penpal-turned-"fairy godmother".

For most of her life, Zink worked on pieces of fiction for herself and her close friends, among them Israeli poet and writer Avner Shats.

Then came Franzen, "kicking and dragging" her out of her comfort zone.

"My life now really started with Franzen. It's just the truth. I can't deny it. He discovered me, like in a Hollywood movie where Frank Sinatra discovers Judy Garland dancing in the chorus line," Zink, now 52, tells The Sunday Times.

"When you've done something for so long, when writing for just yourself became something of a comfort, it takes real violence to get you out of it. He had to yell at me a bit."

Birds brought the pair together. After reading a New Yorker piece Franzen had written about illegal bird-hunting, Zink sent him a letter in 2011, demanding he pay attention to the plight of birds in the Balkans as well.

He wrote back to thank her and they struck up an odd friendship that saw her e-mailing him five times a day and left him impressed with both her writing and her fervour.

Franzen told The New Yorker: "Every e-mail was so vivid... I said, 'Maybe you should try writing fiction'. And she said, 'Oh, I've done that.' "

Zink, who was born in California, but has been living in Germany for more than a decade, sent him her old manuscripts in 2012. He jumped at the chance to get her published.

He tried his hand at peddling her 1998 piece Sailing Towards The Sunset By Avner Shats - a faux-translation of a novel by Shats, another of her penpals - to no avail.

Meanwhile, Zink, on a whim, sent to a tiny independent press another manuscript, The Wallcreeper - a quirky piece about a pair of American newlyweds who move to Europe and become eco-terrorists.

It ended up selling for a $300 advance. When it hit the shelves in 2014, Zink became a published author at the age of 50.

Along the way, she started working on another novel - just for Franzen's sake.

"He's a commercially successful, big-name writer. He has no influence with little tiny presses. He just couldn't sell an arty manuscript of mine, so I finally said, 'This poor man. Okay, I'll write a manuscript with more commercial potential,'" says Zink.

"It was, I felt, the least I could do. Before him, I'd been writing and writing and I had never thought I'd publish anything. Then he came along and said, 'No, no, you're good enough. You can do this.'"

The new manuscript became Mislaid, a smart and off-kilter comedy about a white woman leaving her husband and starting a new life with her young daughter - by adopting African-American identities.

With the help of Franzen and his agent, it nabbed a six-figure deal with Ecco, an imprint of Harper- Collins.

Published last year, Mislaid landed on the National Book Award longlist for fiction.

Zink, who has in her life been a bricklayer, a secretary and a translator, now seems to be making up for lost time: She is already on her third novel.

Nicotine, which launched this year, came about while she was waiting for Mislaid's release in March last year.

"I wasn't planning to write a novel, but I was vaguely thinking about it - about something to do with smoking and squatters. Then, in March, my agent said, 'You know, there's going to be a New Yorker profile of you in early May and then your book comes out'," Zink recalls.

"And she told me if I had a manuscript to sell between the profile and the release date, I could get a lot of money for it - because New Yorker profiles make you really famous."

With a laugh, she says: "So I said, 'Oh, all right then.'"

She clattered through the bare bones of a new book in a month - writing just the dialogue and setting, "almost as if I were writing a screenplay".

But, Zink recalls, when her agent called her up to report that Nicotine had been snapped up, she sounded "absolutely crushed".

The book had sold for $425,000. "But my agent thought it was worth a million dollars," she says, dissolving into a fit of chuckles. "Well, my publisher was not ready to give me a million dollars. I was like 'I'm so sorry. Maybe next time?'"

Nicotine - which Zink spent another nine months fleshing out after the draft was sold - follows the story of college graduate Penny, who, after the death of her hippie father, heads to Jersey City to reclaim his ancestral home.

She discovers it has been occupied by activist squatters championing smokers' rights, who have named the house Nicotine in tribute to their cause.

Zink says: "Political stuff is easy because everybody talks about that. People are obsessed with politics now. That's the sad truth of the Internet generation. It's made politics into not the last thing people talk about with one another, but the first."

But she has never been one to shy away from politically charged topics: sexuality, race, women's rights.

And for her next work, she has ambitious plans to write about how climate change has been made a convenient scapegoat for problems sparked by the mismanagement of natural resources.

She has, however, been ordered to put the brakes on it for now.

"My editor says, 'Whatever you do, Nell, do not immediately write another novel,'" says Zink.

"Because in my career, I need to progress, right? So she tells me my next book needs to be 'big and ambitious and long'. She said, 'Do not write it next year and do not write it the year after that. Write it three years from now, maybe.'"

• Nicotine ($28.89) is available at Books Kinokuniya.