In an extraordinary twist to the usual defamation litigation, Anthony Julius, the lawyer best known for the legal work he performed for Princess Diana, is seeking to marry the daughter of a client whom he met while researching a case.

Dina Rabinovitch, a London freelance journalist and mother of three, and her husband, a derivatives trader at French bank Paribas in London, instructed Julius, the head of litigation at Mishcon de Reya, last year to act on Dina's father's behalf.

The father, Nahum Rabinovitch, an ultra-orthodox rabbi who lives in Israel's West Bank, alleged that a tiny London publishing company, Peter Halban, had defamed him in a book about the assassination of Yitzhak Rabin.

Dina Rabinovitch travelled with Julius in March this year to see his client – her father – and to take witness statements.

It is understood that following that visit, and the revelation that the defendant was intending to call Leah Rabin, the wife of the murdered prime minister, to give evidence, Julius began settlement discussions in May which reached agreement six weeks later.

Halban, a publisher with an annual turnover of only £70,000, agreed to insert a clarification into the books he had still not distributed.

A clarification also went into Jerusalem Report, the Israeli magazine which had compiled the book from its cuttings.

Together with the book's authors, it is believed Halban paid £40,000 towards Julius' costs, leaving a balance of £32,000 paid by Guido Rauch, Dina Rabinovitch's husband.

While the case was going on Julius and Dina appear to have decided to divorce their respective spouses and marry each other. Julius told his wife at the end of March that he was intending to leave her and Dina Rabinovitch announced that she was leaving her husband a few days later.

Julius moved out of the family home in north-west London in July and Rabinovitch left in November.

It is understood they will not live together until they are married.

Guido Rauch would not comment on the case and Rabbi Rabinovitch and Anthony Julius had not returned our calls at the time of going to press.