Sir Cliff Richard is famous for many things apart from his singing - his almost preternatural youthfulness, his Christian faith and, of course, his failure ever to marry.
So it was rather a surprise when, in a recent interview with BBC Radio 4's Woman's Hour, the 71-year-old bachelor boy became involved in a discussion about bigamy.
Sir Cliff announced - quite out of the blue - that his grandfather was a bigamist.
'His wife, my mother's mother, thought he was killed in the war. It turns out that he left her and let everyone assume he was dead, and set up a new home in Coventry.'
He added that he had never met any of this other family, only saying coyly: 'It's in my book.'
But careful examination of Sir Cliff's substantial 2008 tome My Life, My Way reveals no information at all about a bigamist grandfather, or the family he went on to have.
Instead, he fills 308 pages with a long and detailed celebration of his professional life and good works, but little about his personal and family life - and certainly no bigamous skeletons.
In fact, Sir Cliff has never before acknowledged such an intriguing element in his background - which is probably why, as I discovered this week, many members of his 'other' family have died with no idea they were related to him.
Even those still alive, and who know the truth, have never met him, although research showed he has numerous 'half-cousins' living in Britain, should he ever wish to find them.
There are some other surprises in Cliff's family tree, too. For although he briskly told Woman's Hour that his mother was 'not Anglo-Indian' - as has been suggested in the past - and that he had instead an 'Anglo-Indian stepfather', it turns out that he does indeed have Anglo-Indian blood.
The connection comes through his great-great grandmother, Emeline Josephine Rebeiro, the daughter of an Indian man from Goa, Vitriaus Rebeiro.
One of Cliff's long-established full cousins from his mother's side of the family, Garth Gregory, tells me: 'My mother was Cliff's aunt. They were sisters - my mother Olive and his mum Dorothy. And it is well known in the family that there was Indian blood.'
Indeed, pictures of Cliff's mother Dorothy reveal a raving beauty in the mould of the late Anglo-Indian actress, Merle Oberon.
So what is the truth about Sir Cliff's fractured family?
He was born Harry Rodger Webb in Howrah, outside Calcutta, in 1940.
His father, Rodger Webb, was a manager for a catering company and his mother, Dorothy Dazely, was a British woman who had been born in India to a military family.
They came to England in 1948, joining thousands of British descent who left when India gained its independence. The family were 'destitute' at first; Rodger Webb had only £5 in his pocket. Cliff and his sisters, Donna,
Jacqui and Joan, lived in a single room in Hertfordshire while their father sought work.
'Ours was the kind of hardship that either draws people more closely together, or splits them apart completely,' Cliff said.
Cliff's Aunt Olive also emigrated from India and lived in Manchester and then in Essex. Olive's son, Cliff's cousin Garth, tells me that he saw the singer a few times in the early days, and remembers the star buying him a bicycle for Christmas, but then they lost touch.
'He is the star of the family, isn't he?' says Garth. 'I don't think my children have even met him. He's not in this country all that much - I don't think he's interested in his wider family.'
Perhaps he should be, though, for it's quite a family tree. The key figure in the story is Cliff's maternal grandfather, William Edward Dazely. He was born in 1896 in Bombay to Edward Dazely, a driver with the 27th Battery Field Royal Artillery, and his wife, Daisy. {Read on}