She was not brought up with religion, but when suddenly asked if she was Jewish at the age of 12, Esther Freud instinctively said: "Yes".
It was during a slightly alienating exchange visit to a family in Germany, and she recalls: "I had never been asked that question before or even thought about it; my mother isn't Jewish, and my father is only by blood. But when asked, to say 'no' seemed a terrible thing.
"The German family were very taken aback. I must have been the first Jew they had ever met. But they became very tender towards me in the end."
It was the beginning of a continuing sense of identification for the writer and former actress who is Sigmund Freud's great-granddaughter and the daughter of artist Lucian Freud. "I identified even more when I started to write my third novel, Gaglow, about my grandmother's Jewish family in Germany, whose lives were changed so dramatically by the Second World War," she says. "That's when I connected with the family in a way I hadn't done before."
Around the time she was writing Gaglow, 16 years ago, Freud moved to the Jewish heartland of north-west London. Suddenly she was surrounded by members of the tribe: "My children were coming home and asking if they could have a barmitzvah," she recalls.
Her life as a comfortably middle-class mother of three who likes spending money on the house in Hampstead she shares with actor husband David Morrissey is a long way from her impoverished beginnings. Freud is perhaps best known as the four-year-old whisked to Morocco by her hippie mother, as vividly retold in her first novel, Hideous Kinky.
"It left me with a love of adventure," she says. "But it wasn't exciting when my mother ran out of money and had to beg - it was horrible."
It was only after they returned and settled in Sussex, where Freud and her sister Bella attended the Rudolf Steiner school where her mother worked as a dinner lady, that she got to know their famous father. "He had not been with my mother since I was born, and my first vivid memory is when he came to visit when I was seven, driving a big expensive car. He was glamorous, elegant and from a different world. He told me recently he wasn't very interested in babies or children. But we've been close since I was 12 or 13 when my sister used to take me to London on the train to see him."
From the age of 16, when she moved to the capital herself, she modelled for him. It was a useful job for a hard-up young actress, one that she held on to all the way through her 20s, stopping only after she had her first child.
The last picture Lucian painted of her was a tender portrait of her breast-feeding her son - and like all the others she has no idea where it is, or who owns it. "The dealer sells all his pictures privately, because he always needs money," she says.
So there is no ulterior motive for those children who have gathered round Lucian, now 88, to make sure he is cared for and never lonely. "Those of us who have a close relationship with him share a rota, taking him to lunch or tea or dinner," she says. "I see him every few days - and it turns out he's very sentimental about his children."
Not to the point of remembering to send birthday cards. "But if you got lucky and saw him on your birthday… I remember he gave me a £100 note on my 18th," she says. "I had never seen so much money; it was typical of the way my life has veered between such extremes. "
Lucian famously had an unresolved broiges with his late brother, the broadcaster Clement Freud, so it is only by chance that Esther met her first cousins - Matthew, the PR man who married Rupert Murdoch's daughter, and Emma, also a broadcaster.
"I met Matthew at Bond Street tube and he brought me home to where he was living. I sat in the room chatting and chatting with him and Emma, and we have remained friends ever since.
"Clement was a bit scary. But when I wrote Gaglow he took me for lunch, and we really got on. The broiges was still going on because after a lot of very charming talk, he told me he believed my father was illegitimate. He was still getting those digs in."
While some observers have commented that Freud chose another scary and slightly aloof man for her partner of 20 years, she says they have got it wrong. "David can be a bit broody and distracted, but he's not at all frightening."
Morrissey has enjoyed the acting success Freud never managed to emulate. Like the heroine of her seventh novel, Lucky Break, which follows a pattern in being semi-autobiographical, she was asked to leave drama school after two years. It was a crushing rejection which accelerated her writing career. "I was always scribbling during rehearsals, and after Hideous Kinky I did one more play, but I was no longer enchanted."
She has no regrets about becoming a writer. "After all that rejection, to just create something and have someone say 'I really like it' is very gratifying."
'Lucky Break' is published on April 4 by Bloomsbury, at £11.99.
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