Commemorative stamps to mark the wedding of Prince William and Kate Middleton have gone on sale, just over a week before the big day.
Produced with the approval of the monarch and involvement from William, they feature William and Kate's official engagement portraits taken by fashion and celebrity photographer Mario Testino.
The formal image - on the £1.10 stamp - was taken in the Council Chamber of St James's Palace, while the informal image - on the first class stamp - shows the couple in the palace's Cornwall Room.
Royal Mail said it is expecting strong demand for the collectibles, with its website already receiving thousands of visitors from the UK and around the world wanting to find out more about the stamps.
Stephen Agar, of Royal Mail, said: "It is a great honour to commemorate this very special event through this set of stamps. As the nation gets set to celebrate we are proud to be able to offer this everlasting reminder of such a historic occasion."
This is the third time Prince William has appeared on a Royal Mail stamp.
He featured on a sheet of stamps to celebrate the Queen Mother's 100th birthday on August 4, 2000. Three years later he became the first member of the Royal Family to have a set of stamps produced to celebrate their 21st birthday.
And the royal wedding stamps mark another first, as William is the first of the Queen's grandchildren to have their wedding commemorated on a set of stamps.
The stamp sheet, costing £3.12, consists of two 1st class stamps and two £1.10 stamps. The first class stamp marking William and Miss Middleton's wedding will cost 46p as the cost of a first class stamp increased by 5p from April 4. The new £1.10 royal wedding stamp covers the postage of letters and cards, weighing up to 20g, sent worldwide.