On July 5, 2017, Song and Descendants of the Sun co-star Song Joong-ki announced through their respective agencies that they were engaged. They married in a private ceremony on October 31, 2017 at Youngbingwan, Hotel Shilla in Seoul, amid intense media interest across Asia. It was attended by the couple's closest family and friends, including actors Lee Kwang-soo, Yoo Ah-in, and Park Bo-gum who also played the piano at the wedding reception.