As every diligent loyal subject to The Crown knows, today is Queen Elizabeth II's birthday.
Britain's longest serving monarch is 92 years old today and will be celebrating with a star-studded birthday party at the Royal Albert Hall that will feature musicians from around the Commonwealth such as Sir Tom Jones, Kylie Minogue, and Shaggy (which can only be a good thing).
But, as many of you will already be aware, this is not even the Queen's only birthday.
While today is her actual birthday, on another date later in the year - usually the second weekend of June - she will celebrate her birthday all over again.
I mean, as if the Queen doesn't have enough. She has loads of money, adoring fans, and literally lives in a palace. She probably doesn't need two birthdays, so why does she have them?
Well, it actually dates back to 1748 and the reign of George II and, as you might expect given that this is Britain we're taking about, it has a lot to do with the weather.
You see, George II's birthday fell in November and, being a modest, understated guy, he wanted a big parade to mark the occasion.
However, it was thought that having a huge military parade and procession in November would be a bit of a waste of time given what the weather is usually like in Britain at that time of the year.
It was decided that instead of forcing everyone out onto the streets in the cold and rain, his birthday celebrations would simply be moved to a time of the year when we could count on the weather being better - or at the very least, not as bad.
Luckily, in the Spring there is a traditional military parade called 'Trooping the Colour' - a big old march of all of the regiments in the British Army on Horse Guards Parade in London.
So they just tagged onto the back of that and combined the existing parade with the King's royal birthday celebrations - and the tradition has stuck.
The actual date changes every year. Last year it was on Saturday 17 June, this year it is scheduled to take place on Saturday 9 June.
The Queen's actual birthday (today, that is) will see her joined by her family for private celebrations before a few of them head out to Kensington for the concert, which will be live on the BBC this evening.
One royal who will probably not be there is the Duchess of Cambridge, who is on maternity leave ahead of the birth of her third child.
The actual due date is not known, but is thought to be any day now.
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