Prince William will become the country's first king to have proven Indian roots after saliva samples revealed direct lineage to the Commonwealth's most populous nation, the Times reported on Friday.
DNA from the second-in-line to the throne's sample was linked to that of a woman now known to have been at least half-Indian, according to researchers at the University of Edinburgh.
It had previously been assumed that Eliza Kewark, the duke's great-great-great-great-great grandmother was Armenian, but DNA passed down the female line revealed that she was at least half-Indian, the Times reported.
University of Edinburgh genetics expert Jim Wilson, who carried out the tests, said the proof of William's Indian roots was "unassailable".
William and his wife the Duchess of Cambridge, who are expecting their first child in July, are yet to visit India.