Son Ga-in (born September 20, 1987), better known mononymously as Gain, is a South Korean singer, actress and entertainer. She is best known as a member of the South Korean girl group Brown Eyed Girls and for her appearances alongside Jo Kwon from 2AM for TV shows We Got Married and All My Love. As a solo artist she has released four solo albums.
On May 9, 2014, both Gain's and Ju Ji-hoon's agency confirmed that they are dating <3