YoonA was a guest on the December 5 installment of KBS 2TV's 'Happy Together 3' and mentioned that she recently had a phone conversation with her first love.

SEE ALSO: "They're so good, this is what K-pop should be like," Girls' Generation's past live performance gains spotlight after 8 years

She explained that she had been friends with him back in elementary school, which was about eleven years ago.  She would have felt a bit uncomfortable if he had kept going on about her being in Girls' Generation, but he rather casually said, "To think that the YoonA I knew has come this far!"

She continued, "Worried that he might mention it first, I said, 'I used to like you in the past!'" and the MCs laughed, saying she was trying to put on a tough appearance.

YoonA explained that he had already known about her feelings, but jokingly added he was probably filled with regret now.