The Trooping of the Colour has kicked off as the parade to celebrate the Queen's official 91st birthday gets underway.
Thousands are expected to be in London for the big day, with crowds already lining the streets.
The Trooping involves over 1,400 soldiers, 200 horses, and the members of the Royal Family of course.
The troops began to form this morning and the Queen left Buckingham Palace at 10.45am for the grand procession with the Household Cavalry.
At 1pm, the Queen will head out onto the balcony of the Palace to wave to the crowds and watch the flypast. More on all the details of where you can catch that here.
Here's how it's been shaping up so far:
The day of celebration goes ahead after the Queen's birthday message struck a solemn tone, as she praised the country for being "resolute in the face of adversity".
In a message to mark her official birthday, she said: "Today is traditionally a day of celebration. This year, however, it is difficult to escape a very sombre national mood. In recent months, the country has witnessed a succession of terrible tragedies."