Which performer on the EP "Twinkle" also performed on the Korean stage musical version of "Mamma Mia"?
Girls' Generation-TTS:  It is composed of three Girls' Generation members: Taeyeon, Tiffany, and Seohyun. Girls' Generation-TTS:  The group has released three EPs: "Twinkle" (2012), "Holler" (2014), and "Dear Santa" (2015). Seohyun: Seo Ju-hyun (born June 28, 1991), known professionally as Seohyun, is a South Korean singer and actress.
i don't know