The seventh Duke of Westminster is only 25 years of age, a godfather to Prince George and now "owns half of London".
Hugh Richard Louis Grosvenor - who was previously known by the honorary title Earl Grosvenor - inherits his father's £9 billion estate and the family's country seat Eaton Hall in Cheshire - home to the Grosvenor family since the 15th century.
Here's 8 things to know about him:
1. He is one of four siblings and the only son of the late Duke of Westminster and his wife Natalia.
2. He was the youngest and the wealthiest of Prince George's godparents when he was picked by the Duke and Duchess of Cambridge in 2013 for the role supporting the future king.
3. He used to study countryside management at Newcastle University.
4. He had 800 guests at Eaton Hall for his "black tie and neon" 21st birthday party - where Michael McIntyre and Rizzle Kicks provided the entertainment - which reportedly cost £5 million. Guests who wanted to give him a present were asked to add to Hugh's large wine collection.
5. He works as an account manager for bio-bean - a green technology company which recycles waste coffee grounds into advanced biofuels and biochemicals.
6. The Tatler List declared that after inheriting his father's estate he would "own half of London".
7. Hugh was not educated at boarding school - unlike William and Harry - but enrolled at a state primary before going to a private day school close to home in Cheshire.
8. Hugh is likely to have to take on responsibility for the Westminster Foundation - the charitable body which manages the philanthropic activities of the Grosvenor family. It was set up in the 1970s and since then has awarded more than £40 million in grants.