The Queen is to formally welcome the king and queen of Spain to the UK as they begin a three-day state visit.
King Felipe and Queen Letizia will be greeted by the Queen and the Duke of Edinburgh at Horse Guards Parade later.
The trip is the first state visit by a Spanish king to the UK since Felipe's father, Juan Carlos, came 31 years ago.
BBC royal correspondent Nicholas Witchell said UK leaders hope the trip will foster understanding between the two countries over Brexit.
It is expected to be Prince Philips's last state visit before he retires from public duties after the summer.
