The Prince of Wales is due to join 150 war widows for a service of remembrance at the Cenotaph in London.
The Prince, who is patron of the War Widows Association, will lay a wreath and also attend a reception.
Later the Queen is expected to attend the Royal Festival of Remembrance at the Royal Albert Hall.
The annual event is hosted by the Royal British Legion as a tribute to those that made the ultimate sacrifice.
The festival comes on the eve of Remembrance Sunday at the Cenotaph.
Other royals due at the Royal Albert Hall include the Duke of Edinburgh, the Prince of Wales and Duchess of Cornwall, and the Duke of York, Earl and Countess of Wessex and the Princess Royal.
Veterans and their families will also be present at the festival, which will see Queen guitarist Brian May and singer Kerry Ellis perform and actor Bernard Cribbens and Hayley Westenra give a rendition of For The Fallen.
One of the evening’s traditionally moving moments is the release of poppy petals from the building’s great dome to represent all those who have died in combat.
Another highlight is expected to be the Book of Remembrance carried into the hall by Royal Marine Lance Corporal Ram Patten, accompanied by the “March For Honour” teams who have been trying to raise £1 million for the Legion.
The serving and ex-servicemen have been marching across the UK since 4 November in four groups – walking a mile for every British military life lost on operations in Iraq and Afghanistan since 2001.
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