The singer/actor and Turner, who stars on "Game of Thrones," announced their happy news Sunday on social media.
Jonas posted a pic of their hands together with Turner sporting her new engagement ring and a caption which read "She said yes."
That sparked congratulations from the masses, including Jonas's father, Kevin, who tweeted the Instragram of the engagement photo.
"We are so thrilled that @Sophiee_Turner said yes to our son @joejonas," the elder Jonas said. "Welcome to our family!"
Danielle Jonas, who is married to Kevin Jonas Jr., said on social media that she's excited to get a new sister-in-law.
"When you realize you want to spend the rest of your life with someone," Danielle wrote. "You want the rest of your life to start as soon as possible."
"I am so happy for you two," she added. "And I am thrilled to have a sister in law finally I been waiting!!! Love you both."
Even Joe Jonas's ex girlfriend, singer Demi Lovato, is thrilled.
She liked the engagement photo and shared her good wishes in the comments section.
"HUGE CONGRATS," Lovato wrote. "Sooooo happy for the both of you!"