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.

For the post, the mom of three included a short but sweet message, writing, "Happy Father’s Day, Papa (before and after!) We love you! G, C & L 💖." Middleton also tagged the

Trooping the Color is the royal family's annual celebration honoring William's father, King Charles, who turns 77 this November