"Ahh! Congratulations to my brother... and sister in law to be on your engagement. I love you both so much," Nick wrote Sunday alongside the same photo shared by Turner showing her wearing a large diamond ring while resting her hand on top of Joe's.
"Congrats @joejonas and @sophiet so happy to welcome you into the family!" added Kevin who also shared the same image.
Turner, 21, announced her engagement to Joe, 28, Sunday writing, "I said yes." The private couple are known to have been dating since at least December 2016.
Previously, the Game of Thrones star said "I'm very happy," when asked about dating the pop star in July.