Jessica congratulates her little sister Krystal's birthday by sharing a childhood photo of the two.

On October 24th, Jessica updated her Weibo and wrote,"Happy Birthday~Unnie love you a lot. Happy birthday my dearest sis ^^ There was a time when i used to be... Taller than you!", and uploaded along the photo which shows young Jessica and Krystal sitting inside a toy hellicopter.

Meanwhile, Krystal has been revealed to go back doing her schedules normally after her fainting incident at SMTOWN in Shanghai.