Sophie Turner and Joe Jonas announced their engagement on Oct. 15, and Maisie Williams is over the moon. On Monday, the Game of Thrones actress reposted Sophie's engagement ring Instagram photo and congratulated her BFF with a sweet message. "Congratulations to my beautiful girlfriend on her engagement 💍," she wrote. "This is just one of MANY life milestones we'll share. Love you both 💗 #mophie #jophie #holymoly." Sophie and Maisie have been friends since they were 13 and 12 years old, respectively, when they were cast as sisters on Game of Thrones, so we wonder if Maisie will serve as one of Sophie's bridesmaids?