Princess Diana's niece Lady Kitty Spencer could lose inheritance

Princess Diana's brother is set to cut his eldest daughter Kitty out of his estate. Photo / Getty Images

Princess Diana's younger brother Earl Spencer has revealed he will leave everything to his son, despite having an older daughter.

According to The Sun, William and Harry's uncle is planning on leaving the family estate to his 25-year-old son, Viscount Louis Spencer, instead of his first-born child, Lady Kitty, 28.

In doing so, he'll be abiding by the archaic tradition of the eldest son in the family inheriting property, titles and fortunes.

Kitty is the eldest child of Earl Spencer. Photo / Getty Images

"Is it any fairer that the eldest child gets it instead of the eldest male?" he asked The Sunday Telegraph.

"Whatever you say is a selection."

His decision may be because he himself inherited his own family estate over his sisters, Lady Sarah McCorquodale, Jane Fellowes, Baroness Fellowes and the late Princess Diana.

Princess Diana's younger brother Earl Spencer has revealed he plans to leave the Spencer family estate to his son despite having an older daughter. Photo / Getty Images

The Althorp Estate is located in the district of Daventry in Northamptonshire, and includes a Grade I listed stately home, along with 50 square kilometres of woodland, cottages and farms.

The Spencers have owned the property for over 500 years, and Diana lived there herself until she married Prince Charles.

The late princess' grave is located on an island in the middle of an ornamental lake on the estate. Some say it's been designed to protect her body "from ghouls".

The property is also now available for overnight hire, but guests can be expected to fork out over $46,000 a night to stay at the royal estate.

An aerial view of the burial site of Diana, Princess of Wales. The Round Oval Lake is located in the Althorp Estate, home to the Spencer family. Photo / Getty Images