They kept the nation waiting for many years with bated breath over whether they would tie the knot.
And now it seems that the public weren’t the only ones in the dark.
The Prince was so keen to keep their engagement a secret that the only other person who knew was Kate's father, Michael.
Following a romantic proposal on holiday in Kenya, William asked Michael for Kate's hand in marriage when the couple returned from Africa.
The Queen was only informed when, keeping in line with an 18th century law, her grandson called her on Monday morning to ask her permission.
Prince Harry and Kate's brother and sister were told little more than three hours before the announcement was made public.
Prince Harry said: "I am delighted that my brother has popped the question. It means I get a sister, which I have always wanted."
Photo: © Rex