Jonas announced the engagement pretty much the same way all millennial men do these days - with a photo of the wedding ring alongside the caption "She said yes".
The couple's romance has left a distinct Instagram history, with their first appearance on the platform published on the 1st of January this year.
Kit confessed that he had to contact Game of Thrones producers, warning them to plan filming schedules for the entire cast and crew around his big day.
In a post shared to Instagram by Jonas on Sunday, the 28-year-old revealed that he and Turner are getting married.
The pair have been dating since 2016.
Younger brother Nick Jonas also shared a pic of Joe and Sophie's engagement announcement photo on Twitter. It's frustrating [that] it's the most mundane things that make the news - how boring!
"You're making me blush", she said.
Jonas has dated a few different celebrities in the past, including AJ Michalka, Demi Lovato, Camilla Belle, Ashley Greene, Taylor Swift and Gigi Hadid. "There are really no other headlines?"