There’ll be performances from actors, musicians, bands, dancers and the military and the event has been designed to reflect The Queen’s love of horses, her connections with the Armed Forces and the Commonwealth.
On Sunday, The King's Troop will perform in front of the Queen and it's taken months of training to get them ready.
The soldiers on horseback were first formed in 1946 to be a show piece during ceremonies of state. Simon Parkin went to see them rehearsing.
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