The Hong Kong-born British socialite, whose portfolio includes Princess Beatrice, Poppy Delevingne, and Carey Mulligan, revealed the happy news on Sunday.
The model wife of British actor Idris Elba stood out in a plunging beige gown from the Lebanese designer during her latest appearance at Haute Couture Fashion Week.
The 38-year-old model and actress was joined by close friends and family at the pink-themed bash in London last Friday, co-organised by Harry and Meghan's matchmaker