The Prime Minister David Cameron, Alex Salmond and the Princess Royal are set to join thousands of visitors at the sixth annual Armed Forces Day.
Crowds will enjoy piping, parades and a display by the world-famous Red Arrows as Britain marks the contribution of servicemen and women past and present in Stirling, Scotland.
There will be entertainment in the form of a parachute display and displays by Typhoon and Tornado jets, with Stirling Castle providing the backdrop.
Armed Forces Day was established in 2009 to honour the country's servicemen and women and their families across the Army, Navy and RAF.
More top news
Pensioner's photo evidence being used in the hunt for two men captured on a stolen bike in an incident that saw him suffer a heart attack.
Footage filmed at an industrial estate in Stourbridge has emerged showing suspected migrants from Calais fleeing a lorry.
A baby sloth named Edward after his impressive Edward Scissorhands-like claws is being hand-reared with the help of a special teddy bear.