More than 1,000 beacons will be lit across the the UK on Thursday to celebrate the Queen’s 90th birthday.
The fires, which have traditionally been used to celebrate royal jubilees, weddings, coronations and special birthdays, will be placed on top of mountains, churches or castle battlements, on town and village greens, farms, country parks and along beaches.
Well-wishers are expected to sing Happy Birthday to the Queen when she goes on a walkabout close to her Windsor Castle home later to acknowledge the good wishes of the public.
And in the evening the night sky over her Berkshire home will be lit up by a beacon, started by the Queen, the first in a chain of hundreds that will spread across the country and the globe.
After the Queen lights the beacon, heir to the throne Charles, will also stage a lavish private family dinner for the royal matriarch in the evening in the castle - with the event said to be being overseen by his trusted former valet Michael Fawcett, according to the Press Association.
Brave members of the Army Cadet Force will even take beacons to the top of the UK’s four highest peaks: Mount Snowdon in Wales, Ben Nevis in Scotland, Scafell Pike in England, and Slieve Donard in Northern Ireland.
In a message to beacon lighters, Prince Charles said: “I am delighted that so many people throughout the United Kingdom are coming together to light beacons in celebration of my mother, The Queen's, ninetieth birthday.
“It is a wonderful gesture which I know has deeply touched Her Majesty.
“Beacons are to be lit on mountaintops, on beaches, in farmyards and on church towers, uniting us all in our heartfelt appreciation of The Queen's lifetime of service to the United Kingdom and other Realms, and to the Commonwealth.
“Since time immemorial, the light of beacons has relayed important messages across the land.”
One unusual tribute will see the Houses of Parliament lit up red, white and blue in honour of the Queen's milestone.
And traditional gun salutes will thunder across the capital when 41 volleys are fired by the King's Troop Royal Horse Artillery in London's Hyde Park, and 62 rounds by the Honourable Artillery Company close to the Tower of London - the extra 21 volleys for the citizens of the City of London to show their loyalty to the monarch
Later today the Queen, accompanied by the Duke of Edinburgh, will unveil a plaque marking The Queen's Walkway at the foot of Castle Hill before going on a walkabout with Philip.
The walkway - a four-mile self-guided walking trail of Windsor by The Outdoor Trust - has been created in honour of the Queen becoming the country's longest reigning monarch.
When the Queen became the nation's longest-reigning monarch last autumn - passing Queen Victoria's record - she remarked that living to a ripe old age can bring many anniversaries: "Inevitably a long life can pass by many milestones. My own is no exception."
In June, thousands of well-wishers will gather for celebrations planned to mark the Queen's official birthday.
A series of events will be staged, from a St Paul's Cathedral service of thanksgiving to the traditional Trooping the Colour ceremony, and a sit-down celebration for 10,000 people on The Mall called the Patron's Lunch.