Pierre Casiraghi celebrates his 27th birthday on Friday 5 September.
The handsome royal is expected to mark the occasion surrounded by his family and close friends.
To celebrate Pierre's birthday, HELLO! Online has gathered ten facts you may not know about Princess Caroline's son…
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Pierre Casiraghi is the fourth-in-line to the Monegasque throne
1. Pierre was born on 5 September 1987 at the Princess Grace Hospital in La Colle, Monaco to parents Princess Caroline of Monaco and Stefano Casiraghi.
2. He is the grandson of the late Princess Grace of Monaco and his uncle is Prince Albert II of Monaco. Pierre is currently fourth-in-line to the Monegasque throne.
3. When Pierre was three years old, tragedy struck the family when his father, Stefano, died in a speed boat crash. After the accident, Princess Caroline decided to move to the family's French country estate in St Remy de Provence, where Pierre and his siblings Andrea and Charlotte were able to grow up out of the spotlight.
A young Pierre Casiraghi pictured with his mum Princess Caroline and older sister Charlotte Casiraghi
4. As a member of Monaco's royal family, Pierre often supports his uncle Prince Albert II and his mother Princess Caroline with royal duties. In early 2007, he joined his mum on a two-week tour of Africa, visiting Burundi, Niger and South Africa.
5. Since 2009, Pierre has been dating Beatrice Borromeo and the loved-up pair are often spotted attending high-profile events together. Many royal watchers are predicting Pierre could be the next Monegasque royal to walk up the aisle.
6. The handsome royal is currently fluent in English, French, Italian and German.
7. In 2013, there was double joy for the family with Pierre becoming an uncle twice as older brother Andrea welcomed his first child Alexandre, and his younger sister Charlotte also gave birth to her first child Raphaël.
Pierre Casiraghi and Beatrice Borromeo have been together for five years
8. During his spare time, the popular royal enjoys swimming, skiing and playing the saxophone.
9. In 2006, he moved to Milan where he undertook a three-year undergraduate course in International Economics and Management at Bocconi University.
10. He currently uses his degree to manage his late father's companies, which he shares managerial duties with his uncle Marco.