A unique fact that many might know about Queen Elizabeth II is that she has two birthdays, with her 'real' one taking place today (Thursday, April 21).

However, many might wonder why she has two in the first place, and when the second one takes place.

It is a tradition that can date back to the 1700s with a previous monarch having a summer celebration for the public outside of their actual birthday.

Here is why Queen Elizabeth has two birthdays and what she does to celebrate them.

News Shopper: The Queen has her actual birthday on April 21 (PA)The Queen has her actual birthday on April 21 (PA) (Image: PA)

Why does the Queen have two birthdays?

According to The Metro, the concept of having two birthdays started in 1748 by King George II who wanted to throw a public celebration to mark the occasion of his birthday.

However, as he was born in November the likelihood of the weather holding out for such a celebration was slim.

Therefore he made two birthday dates, one for public celebration in the summer, and one for private in November.

This tradition has continued for over 250 years, with Queen Elizabeth now also celebrating two birthdays a year with one celebration in April and a public, official event in June.

The summer birthday falls of the second Saturday of June each year, so will be June 12 for 2022.

How is the Queen's birthday celebrated?

For the official event in June the Queen's birthday is marked by the Trooping of the Colour parade

The occasion is marked publicly by gun salutes in central London at midday: a 41 gun salute in Hyde Park, a 21 gun salute in Windsor Great Park, and a 62 gun salute at the Tower of London,’ states the official Royal Family website.