British tycoon Sir Richard Branson's socialite son is a married man after exchanging vows with his fiancee in South Africa on Wednesday (06Mar13).

Sam Branson wed his girlfriend Isabella Calthorpe at Ulusaba Lodge, his father's private game reserve, in front of a star-studded crowd which included members of Britain's royal family and Kate Winslet, who is married to Sir Richard's nephew Ned Rocknroll.

Princesses Beatrice and Eugenie were in attendance, while their cousin Prince Harry's rumoured girlfriend Cressida Bonas, the bride's half-sister, sang for the 300 guests.

Sir Richard took to to share his excitement before the ceremony, writing, "Happy day: Sam Branson to marry his lovely Isabella under the stars in beautiful Ulusaba surrounded by those they love."

Documentary filmmaker Sam, 27, has been dating actress Isabella, 33, for six years, and proposed last year (Jun12) during a romantic trip to Madagascar.