Royals See the Sweet Card That George, Charlotte and Louis Made for 'Gan-Gan' the Queen and Prince Philip The Queen, 94, and Prince Philip, 99, are celebrating their 73rd wedding anniversary at Windsor Castle By Simon Perry Published on November 20, 2020 04:45 AM Share Tweet Pin Email Trending Videos Photo: Chris Jackson/Getty Images; Kensington Palace Happy anniversary, Gan-Gan! The sweet card that Prince George, Princess Charlotte and Prince Louis made for Queen Elizabeth and Prince Philip to mark their 73rd wedding anniversary has been revealed. Kate Middleton and Prince William unveiled the brightly-colored card their kids made that was featured in the official palace photo to celebrate the couple's milestone on Friday, November 20. "Gan-Gan" is what George, 7, Charlotte, 5, and Louis, 2, call the Queen – who has eight great-grandchildren in total. The sweet artwork was shown in a simple social media post which added the Cambridge family's congratulations to the couple: "Wishing a very happy wedding anniversary to Her Majesty The Queen and His Royal Highness The Duke of Edinburgh!" Kensington Palace The Queen, 94, and Philip, 99, are celebrating their anniversary at home at Windsor Castle, where the portrait of them looking at the card, and other mementos and cards from family, was shot earlier this week. Queen Elizabeth wearing her honeymoon brooch on her wedding anniversary in Nov. 2020. Chris Jackson/WPA Pool/Shutterstock The Queen and Philip look thrilled with the colorful card. Like millions of people around the world, they have been separated from their families for long periods of time amid the ongoing pandemic and have missed the chance to entertain or greet and hug their great-grandchildren. It is another milestone in a lifetime of landmark moments. Next year, the couple — and their family — will mark Philip's 100th birthday. It was also recently announced that plans are underway for the Queen's Diamond Jubilee celebration for her 70 years on the throne in 2022. Can’t get enough of PEOPLE‘s Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! Last year, they spent the anniversary apart — with Philip in Norfolk, about 110 miles from London — and the monarch had duties in London. She spent some of the day holding audiences and then later she was out on a visit and joked when she was asked to sign the visitor's book: “Well, of course I know what the date is!”