f(x)'s Amber recently shared a baby photo of fellow group member Krystal as a special treat for fans, and it looks as though Krystal decided to return the favor.

On May 2nd, Krystal shared the photo above (right) on her official me2day page and wrote, "amber josephine liu's 3rd birthday party."

Fans were a bit surprised to see the photo of Amber in a lovely flower-print dress, as she is now known for her tomboyish charm. The photo was taken on Amber's birthday, September of 1995.

"Amber was very girly at one point!" the fans wrote, along with, "She was so cute," and "Oh I never knew her middle name was Josephine."

Source & Image: Krystal's me2day, TVReport