WCXX

Helene and Frank (who was happily married) would never meet; he died in 1969, the year before Helene published their correspondence in a volume named for the bookstore's address: 84 Charing Cross Road. It was not her first book (her brilliant but sadly out of print memoir Underfoot in Show Business appeared in 1962), but it was the one that made her famous. It was the one that would be turned into a radio play, a stage play and a film starring Anne Bancroft and Anthony Hopkins. It was the one that, ultimately, brought her 16-year-old cousin to her door.

When I arrived for that first visit, the apartment was full of the books acquired from 84 Charing Cross Road. Nearby were the desk on which she had written her half of the famous correspondence, the typewriter on which she'd typed it, and the piles of letters that had arrived for her daily since its publication (as her address appeared numerous times in every edition, they would continue to do so until the end of her life).

That first day, she located a rolled-up family tree and unfurled it on her dining table. There – she pointed to one end of the long horizontal document – were her people, and there – she pointed to the other – were mine. To find the connective tissue between us we'd have had to go generations back. But we agreed to call ourselves cousin in perpetuity.

"I brought her Hanff out of the closet!" was Helene's favourite way to introduce me, and often enough, when I came over to visit, there was a fan there, oohing over the celebrated books, soaking up the outsized personality so familiar to readers of 84. "This is Jean Hanff," Helene would crow. "She was ashamed of her middle name until she met me!"

This was true enough. I'd been horrified when I first understood that I was saddled with a bizarre thing like "Hanff" – my maternal grandmother's maiden name – while my friends had pretty or at least comprehensible middles like "Cindy" or "Ruth".

Mainly, I pretended it wasn't there. But when I proposed a review of 84 to Seventeen Magazine a few months after first meeting Helene, and when that review was published (my first ever publication), my name appeared as Jean Hanff Korelitz, and so it has been ever since. In fact, nothing irritates me more than reporters or reviewers who blithely leave it out.

When I lived in England, people occasionally took it upon themselves to present me as a double-barrelled "Jean Hanff-Korelitz", which I found ridiculous (remind me: in which branch of the peerage are the Hanff-Korelitzes to be found?), but I loved England so much that I let it go.

Our mutual love of England ran a very close second to our shared love of books and writing. Like Helene, I had been infected by English literature from a young age, and had grown up hungering for what she called "the England of English literature": "I live for the day when I step off the boat-train and feel its dirty sidewalks under my feet." She had to wait until she was 54, until 84 Charing Cross Road's UK publication, to get there. I was luckier. I made it to London aged six, an event I recorded in my diary with coloured markers to convey my sense of occasion. And in 1983, after graduating from college, I returned to spend two years at Cambridge University.

One day, during my time at Cambridge, I caught the train down to London to meet Helene. After that first visit in 1971 she came regularly to England, where she was entertained with immense kindness by her publishers, Andre Deutsch and Diana Athill, and treated to the kind of celebrity whirlwind (newspaper profiles! Television interviews!) few writers experience. The occasion on that particular day was especially meaningful for my cousin, who had gathered many of her friends to witness the unveiling of a commemorative plaque at the address she had made famous. Marks & Co had departed Charing Cross Road years before, but because of the round bronze marker, fans of 84 would always have a place to which they could make their pilgrimage. The sight of her, on the "dirty sidewalk" of the city she had loved from afar all her life, standing in front of "her" plaque, is one of my most satisfying memories of Helene. How amazed would she have been to know that, after her death, the apartment building at 305 East 72nd Street would formally name itself Charing Cross House in her honour?

She lived long enough to read my first novel, published in 1996. She also lived long enough to let me know how little she thought of it. "Why would you write this?" she asked me with her usual directness, and, of course, she was right (I would go on to write far better novels, thank goodness), but I had waited a long time to have a book published, and I was hurt when I hung up the phone. Five minutes later she called back, in tears. "I'm sorry," she wailed. I was stunned, and tried to persuade her that it was nothing, but she didn't believe me, and she was right; when she died the following year there was still that skein of discomfort between us.

On the day of her funeral, I travelled into Manhattan from my home in New Jersey. I had a few hours to kill before the service, so I visited the flea market on West 26th, and when I turned up at the Riverside Memorial Chapel with an old wooden footstool I had just purchased, one of the doormen offered to carry my "shiva stool" upstairs to the chapel. I burst out laughing, and I know Helene would also have appreciated this moment of absurdity. We were both such terrible Jews that I had no idea what a "shiva stool" was, and I felt quite sure Helene wouldn't have either. Nevertheless, in all the years that have passed since, I have never been able to look at my old green footstool without thinking of Helene. I think she would have loved that, too.

Jean Hanff Korelitz's sixth novel, 'You Should Have Known', will be published by Faber next month (£12.99)