Selena Gomez -- Lovato's longtime pal and the ex-girlfriend of Joe's younger brother Nick -- also responded to the exciting news, writing: "Congratulations."
Meanwhile, Turner posted the same engagement photo to her Instagram, and got her own congratulatory comments from her famous friends.
"Congrats," supermodel Emily Ratajkowski wrote to the 21-year-old actress.
Sharing her surprise upon hearing of the proposal, Modern Family's Sarah Hyland later remarked, "GURL. WHAT?!?!?!"