Which performer on the EP "Twinkle" also performed on the Korean stage musical version of "Mamma Mia"?
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. Seohyun:  Apart from her group's activities, she has established herself as an actress, notably through her participation in the original and Korean versions of stage musicals including "Moon Embracing the Sun", "Gone with the Wind" and "Mamma Mia".
i don't know