소녀시대-태티서 (Sonyeoshidae-TaeTiSeo), also known as Girls' Generation-TTS, is the first official sub-group of South Korea-based girl group, 소녀시대 (Girls' Generation), formed by SM 엔터테인먼트 in 2012. The unit is composed of three Girls' Generation members, Taeyeon (태연), Tiffany (티파니) and Seohyun (서현) (leader). Their first album, Twinkle, was released on iTunes and other music service sites on April 29th, 2012, while the physical album dropped on May 2nd, 2012.