The guests had a wish for the birthday girl: Stay forever Young.
Tiffany Young recently celebrated her 30th birthday which gave an opportunity for all the eight members, including Young, of now-on-hiatus Girls' Generation to hold a reunion.
Young, who has relocated to the United States, was back in Seoul early this month to stage a solo concert. Aug 1 marks her birthday while Aug 5 is linked to the girl group's debut in 2007.
At her Seoul show, Young told the crowd: "I think I'm able to take on new challenges because I have the (support of the Girls' Generation) members."
One of them, Seohyun, who had a cameo spot in Young's concert, said: "It feels like you've arrived from overseas to perform like Lady Gaga or Christina Aguilera. Come to Korea often."
Young had her own wish for her gang at the gig, saying: "Each of the members is tackling new things. Please support them."