It looks like Queen Elizabeth's historic 70-year reign isn't the only milestone that the royals are celebrating this weekend.
In case you missed it, today also marks baby Lilibet's first birthday, and Kate Middleton and Prince William celebrated the occasion with a very special message. As they kicked off the day's events by visiting Cardiff Castle in Wales, they also took some time to post well wishes for their niece on their official Twitter page. They wrote, "Wishing a very happy birthday to Lilibet, turning one today!" The pair also added a playful balloon emoji.