The Queen is to address the Scottish Parliament as part of its 20th anniversary celebrations.
The Prince of Wales will join his mother as she makes a speech to Members of the Scottish Parliament in the debating chamber.
The ceremony takes place almost 20 years to the day since the Parliament officially assumed its legal powers on July 1, 1999 following devolution.
Some of the young people born on that date will join MSPs to hear the Queen's speech.
The Crown of Scotland will be brought in a procession from Edinburgh Castle to the Parliament and enter the chamber, along with the Scottish Parliament Mace, to a fanfare sounded by the Royal Conservatoire of Scotland, ahead of the Queen's arrival.
After the ceremony, the Queen and Charles, who is known as the Duke of Rothesay in Scotland, will attend a reception in the Parliament's main hall and sign the visitors book.
The ceremony is part of a year-long programme of events to mark two decades of devolution.