You would be forgiven for not realising quite how many cousins Prince William and Prince Harry have.
We all know about Peter Phillips, Zara Tindall, Princess Beatrice, Princess Eugenie, Lady Louise Windsor and James, Viscount Severn, but that's just from Prince Charles's side. What about their mother’s family? Diana had three siblings and they all have children of their own - all of whom can count Prince William and Prince Harry as their first cousins.
Diana was born into the aristocratic Spencer family and grew up on the Althorp Estate in Northampton - a 100,000 sq. ft, 90-room home which will one day be inherited by a man dubbed by Tatler as a ‘Top Eligible Bachelor’.
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Louis Frederick John Spencer, Viscount Althorp, 27, was born on March 14, 1994 to Charles Spencer, 9th Earl Spencer and Victoria Lockwood at St Mary’s Hospital, Paddington.
Louis was the fourth child born to the pair who already had three daughters, Lady Kitty, Lady Eliza and Lady Amelia. He also has younger siblings from his father’s next two marriages: Edmund, Lady Lara and Lady Charlotte.
Louis - who has been praised for his likeness to his cousin Prince Harry - is a nephew of the late Princess Diana, Lady Sarah McCorquodale and Jane Fellowes, Baroness Fellowes.
He grew up in Cape Town with his elder sisters but later moved to the UK and studied at the University of Edinburgh.
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When he was born, he quickly became the poster boy for primogeniture - a historic rule that unseats any female heir if a younger brother is born.
The rules of primogeniture were altered in the Succession to the Crown Act 2013, meaning that any younger brother born after this date can no longer leapfrog an older sister.
As the rule still applies to the Spencer family, the oldest daughter, Lady Kitty Spencer, spoke about how she feels knowing that her younger brother will one day be the 10th Earl Spencer.
She said: "Primogeniture can be a tricky topic, because as times are changing, attitudes are as well. We've grown up understanding that it's Louis to inherit, and Louis will do an incredible job."
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Princess Diana's brother, the current Earl Spencer, explained in 2015 that he was happy with the tradition.
He said: “I would be totally relaxed about Kitty inheriting it, but... if I chose Kitty it would be against all the tradition that goes with Althorp.”
The impressive stately home, which was built in 1508, measures in at 100,000 sq. ft and boasts 90 rooms, incredible grounds and a portrait gallery. The family also own homes in London, Norfolk, Warwickshire and South Africa.
Following his appearance at Prince Harry’s wedding in 2018, many were desperate to know if the handsome aristocrat was single.
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He has even found a fan in award-winning singer Nicki Minaj. The pair met after a show in London and Minaj shared the encounter with her fans on Instagram.
She captioned the pic: "The Royal Family stopped by. @louisspencer Nephew of Princess Diana - he said he wants to marry me #LONDON #ThePinkprintTOUR"
Friends of Louis's have described him as a quiet man and a talented actor, reports The Telegraph.
One told the paper: “He’s super private and gets on quietly with his thing. He’s a very talented actor and, I think, will be a brilliant one. You’d like him. He’s very low-key and genuine, decent and kind – and tall.”