The Prince of Wales is enjoying the summer break with his three children, Princess Charlotte and Prince Louis – the last before his eldest son moves out of the family home to board at Eton.

However, they could be interrupting their summer holiday for a special celebration, as William’s close friend and godfather to Prince George and Prince Archie, Hugh Grosvenor, is marking a special family milestone.

The 7th Duke of Westminster and his wife Olivia Henson’s daughter Cosima is turning one on 27 July. While the notoriously private couple are unlikely to mark their first year of parenting publicly, they will likely be throwing their baby girl a first birthday party to remember.

Hugh Grosvenor and Olivia Henson’s family

Cosima Florence Grosvenor, whose name means order, harmony or the universe, four months after the pair announced their pregnancy.

In a statement released on 27 July, the new parents said: “The Duke and Duchess of Westminster are thrilled to announce the birth of their baby daughter.”

The statement continued: “Both the Duchess and Cosima are doing well. The Duke and Duchess now look forward to spending this special time together as a family.”

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Hugh and Olivia at Chester Cathedral in Cheshire, with several royals in attendance. Prince William took on the special role of usher during the ceremony, while Princess Eugenie was among the high-profile attendees.

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The bride looked gorgeous in a bespoke Emma Victoria Payne wedding dress paired with the Grosvenor family’s Fabergé Myrtle Leaf Tiara.

Cosima’s inheritance of father’s £10bn fortune

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Worth more than £10 billion, Hugh was one of the most eligible bachelors thanks to his extensive property portfolio, which includes 50 per cent of Mayfair and 300 acres of Belgravia.

Born into one of Britain’s wealthiest families,  became a subject of interest.

At the time of her birth, a source close to the couple “The issue of titles and primogeniture is a matter for Government and Parliament and isn’t something the Duke and Duchess would comment on, certainly not at this stage. They’re just looking forward to spending time together with their baby daughter as a family.”