It is the first time Windsor Castle has hosted the event
A soldier proposed to his girlfriend as the first ever Royal Tattoo at Windsor Castle entertained the crowds.
Emma Jeffrey, from Middlesex, said "yes" to Lance Corporal Gavin Worey after he proposed on Friday.
He was part of the three-day event which is expected to attract up to 20,000 people to watch a host numerous regimental parades and demonstrations.
The Queen and the Duke of Edinburgh are expected to watch the grand finale of the event on Saturday night.
L/Cpl Worey, from the Household Cavalry Coach Troop, arranged for his girlfriend to ride on the back of a horse-drawn 128-year-old regimental coach as part of the parade.
But just before they were due to enter the ring he popped the question.
Luckily for him she said yes and the pair were greeted by cheering crowds.
Miss Jeffrey said: "I couldn't believe what he was saying. I didn't really know what to do, but I said yes.
"He said: 'Give me your hand then' and popped the ring on.
"I am still so shocked, we've not had time to think of a date," she said.
It is the first time the Royal Tattoo has been held at Windsor Castle and includes displays from the Kings Troop Royal Horse Artillery, Household Cavalry, Bearskins, pipes and Busbies.
All profits raised from the event will go to The Royal British Legion.
The event will be aired on BBC1 at 1525 BST on Sunday.