Prince George got invited to a young girl's 6th birthday party and although he was unable to attend, his royal parents had the best response while RSVP'ing to the bash. According to Hello! Magazine, the girl's mother shared on Twitter that she received a sweet RSVP on behalf of Prince William and Kate Middleton. "The Duke and Duchess of Cambridge were immensely touched that you should take the trouble to write as you did to their son, Prince George. It really was most thoughtful of you and Their Royal Highnesses have asked me to send you their warmest thanks and best wishes," a staff member said in a reply in part.