A source told People that the Glee actress and her I Am Number Four co-star have decided to tie the knot in the upcoming months.
"They're very happy about it," the insider said.
Agron sparked speculation about the pair's plan to wed after being photographed with a diamond band on her left ring finger at a press conference earlier this week.
"[It's] something I never like speaking [about]," she told reporters who inquired about the relationship.
Reps for the stars had no comment.