When you're the Queen and you get two birthdays, the second one tends to be more formal – especially for your 90th celebration.

The U.K. will celebrate Queen Elizabeth II's official (though not actual) birthday with its annual Trooping the Colour event on Saturday, when the Queen will inspect more than 1,000 military officers outside Buckingham Palace. Unlike Elizabeth’s star-studded birthday celebration in April, Trooping the Colour will not include any celebrities or popular musical performances. Instead, it will adhere closely to the traditions that have been in place since the 1700s.

The parade itself starts at the gates of Buckingham Palace, and proceeds down The Mall before turning right to reach the Horse Guards Parade and Whitehall. It then turns around and heads back to the palace. The whole event will include several salutes, plenty of military marching music, and a fly-over by the Royal Air Force. The Queen herself will ride in a carriage for the event.

But unlike the Santa Claus parade, there's no use in showing up early with a lawn chair to stake out a prime spot. Trooping the Colour attendance is restricted to 10,000 spectators, with a dress code and an application process that closes in February. Applicants can request up to three tickets at a cost of £30 (CDN$57) each, but requests must be made by physical mail, and they need to include a self-addressed, stamped envelope.

For those applicants lucky enough to be selected for a spot at the parade, the dress code is very specific. Morning dresses, lounge dresses, lounge suits or a jacket and trousers are permitted, according to the Household Division website. Military personnel can wear ceremonial garb, and denim is absolutely prohibited.

The Queen will attend the Patron's Lunch on Sunday, where she will be honoured for the many charities to which she contributes each year.

This weekend will wrap up an extended birthday celebration for the Queen, who actually turned 90 on April 21. Her husband Prince Philip, the Duke of Edinburgh, turns 95 on Friday.