Queen Elizabeth II had a rather quiet celebration for her 94th birthday on April 21, as she isolated with her husband Prince Philip at Windsor Castle amidst coronavirus pandemic. However, one of the benefits of being the queen of England is having two birthdays, and Buckingham Palace is planning something low-key but special for the monarch's second one.

Apart from her original birthday, Queen Elizabeth II celebrates her official birthday with the annual military parade, Trooping the Colour, on the second Saturday of June. As the queen continues to isolate due to the COVID-19 crisis, her official birthday this year, falling on June 13, will be celebrated with a mini version of the official birthday parade.

Head of the Commonwealth, Head of the Armed Forces, Head of State in 16 countries and the longest reigning Monarch in British History. Wife, mother, grandmother and great-grandmother.

Happy birthday, Your Majesty! ✨🎂 pic.twitter.com/fusEVFsAJT

— The Royal Family (@RoyalFamily) April 21, 2020

The small-scale ceremony will replace the grand Trooping the Colour parade and fly-past over Buckingham Palace which were cancelled to maintain social distancing guidelines. Buckingham Palace, the official residence of the queen, confirmed to People magazine that a military salute will take place at the Windsor Castle where the British monarch has been isolating since March 19.

"There will be a small, brief military ceremony at Windsor Castle to mark The Queen's official birthday," a Buckingham Palace spokesman told the outlet.

Details of the event haven't been ascertained yet, and so it remains unclear if other members of the royal family will be able to attend in a socially-distance manner on the ground of the castle. Usually, the 94-year-old is joined by her children, grandchildren, and great-grandchildren on the balcony of Buckingham Palace.

According to Mail Online, instead of hundreds of soldiers, the ceremony will be led by a small contingent of the Welsh Guards followed by a salute at 11 am. It is expected that the queen would watch the ceremony from the castle windows instead of a viewing platform.

Official celebrations to mark a king or queen's birthday in the United Kingdom have been held on a different date than their actual birthday for more than two centuries. The double birthday tradition was started by King George II 272 years ago, as the monarch was born in November and couldn't have a big public celebration due to the weather at that time.

Therefore, King George announced in 1748 that his birthday parade will be combined with an annual military parade in the summer when the weather would hopefully be nice. Since then, the reigning monarchs of England have been celebrating an official birthday in summer.

Initially, Queen Elizabeth II celebrated her official birthday on the second Thursday of June, the same day which her father George VI celebrated his official birthday while he was king. In 1959, after seven years on the throne, the mother-of-four changed it to the second Saturday for convenience. Apart from her two birthdays in England, the queen's special day is celebrated on different dates in Australia and Canada.

🇨🇦 This afternoon, The Queen spoke to the Prime Minister of Canada, Justin Trudeau, via telephone.

Today is Victoria Day, which marks The Queen’s official birthday in Canada.

📷 HM and the Prime Minister during an audience at Buckingham Palace in 2015. pic.twitter.com/PU6oGkQ4of

— The Royal Family (@RoyalFamily) May 18, 2020

Meanwhile, Prince Philip would also be celebrating his milestone 99th birthday later this month. The Duke of Edinburgh will keep the festivities low-key and mark his entry into his 100th year of life with a lunch with his wife at the Windsor Castle, reports People.

Queen Elizabeth II and Prince Philip
Queen Elizabeth II and her husband Prince Philip retired to Windsor Castle, outside London, on March 19. POOL / Alastair Grant

His four children, eight grandchildren, eight great-grandchildren, and other members of the British royal family are expected to wish him via video chat.