"I said yes", she wrote on her post, while the DNCE frontman, 28, shared, "She said yes".
Nick tweeted: "Ahh! Congratulations to my brother. and sister in law to be on your engagement". Congratulations to my brother... and sister-in-law to be on your engagement.
The latest "Game of Thrones" union is one that brings New Jersey ever closer to Westeros.
Sophie and Joe have been dating since November, after they were spotted acting cozy at a concert in the Netherlands.
Joe previously dated fellow celebrities Ashley Greene, Demi Lovato, Gigi Hadid, Taylor Swift, and Brazilian model Daiane Sodre.
"Meet the newest addition to the krew @porkybasquiat", Sophie captioned a cute picture of Porky on Instagram, where she could be seen hugging the dog.
"You do feel like you're living in a fishbowl". While Sophie added on her own page: "I said yes". "There are really no other headlines?" "What's that thing they say?" she continued, "relationships come and go, but friendship is always there".