The shared Instagram account for Kate Middleton and Prince William welcomed a trio of guest posters Sunday, when children Prince George, Princess Charlotte, and Prince Louis took the platform over. The occasion: Father's Day, with a post in tribute to their dad, the Prince of Wales.

After arriving at Buckingham Palace by car, Kate and the children, Prince George, 11, Princess Charlotte and Prince Louis, 7, traveled in a traditional horse-drawn carriage down The Mall. Charlotte sat beside her mother, while her brothers faced backward across from them.