Trooping the Colour is the royal family's annual celebration honoring William's father, King Charles, who turns 77 this November.

Kate Middleton and Princess Charlotte have arrived at Trooping the Colour in style!

The Royal Family and Buckingham Palace are busy preparing to celebrate the King’s birthday in style, with the annual Trooping the Colour celebrations kicking off in a matter of hours

Charles is the head of the Commonwealth, an organization of independent states that includes India and Canada.

Flags have been at half-mast at royal residences and the black armbands will add another sign of respect, with the King having said he was "desperately shocked by the terrible events in Ahmedabad".