The Royal Family pay tribute to the Queen on International Women's Day – see rare photo

Her Majesty is the longest-reigning Sovereign in British history

The Royal Family's official Instagram account paid tribute to the Queen on Sunday in a post in honour of International Women's Day. They shared a black-and-white photo of the monarch in her Grenadier Guards uniform, including hat, sash, and medals. HRH was seated on top of a horse and saluting. The caption for the photo read: "The Queen in her Grenadier Guards uniform during her first Trooping the Colour as Monarch in 1953. Her Majesty is Head of the Armed Forces, Head of the Commonwealth, Head of State in 16 countries and the longest reigning Sovereign in British history. On International Women's Day, find out more about Her Majesty’s life and work via our link in bio. Photo: Press Association #internationalwomensday #iwd2020."

WATCH: Harry and Meghan arrive at The Mountbatten Music Festival

Fans were quick to express their admiration for the Queen, commenting: "Her Majesty has served her country with dignity and honour. Inspirational woman," "Happy International Women’s Day, Your Majesty! Hope you have a splendid day," "So regal, greatest monarch in English history," and: "Happy Women's Day to Her Majesty; the strongest among all!"

READ: Prince Harry and Meghan Markle make surprise appearance with the Queen at church

The Queen is the longest-reigning monarch in British history

Her Majesty attended church on Sunday morning as usual, although on IWD she was joined by a couple of family members that royal watchers hadn't expected to see – the Duke and Duchess of Sussex! The couple were all smiles as they attended the service at The Royal Chapel of All Saints in Windsor, which is close to their UK home, Frogmore Cottage. Harry and Meghan are stepping back from their roles as senior working royals at the end of the month and have been attending their last official functions this week. However, they remain on great terms with the Queen.

MORE: Girl power! The queens and princesses who are proud to call themselves feminists

After the momentous meeting at which their future was confirmed, the monarch released a statement, which read: "Today my family had very constructive discussions on the future of my grandson and his family. My family and I are entirely supportive of Harry and Meghan's desire to create a new life as a young family. Although we would have preferred them to remain full-time working Members of the Royal Family, we respect and understand their wish to live a more independent life as a family while remaining a valued part of my family."

Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.