Get To Know TST: Profile, Two-time Name Change, Recent Activities, And More

Meet TST, The Group That Has Changed Its Name Two Times Already

Usually, it is uncommon for a K-Pop group to change its name. Unless there’s a reason behind it, or whether or not they move to a different agency and can no longer use their name, it usually stays until the group is disbanded. To be fair, it is kinda hard to build a reputation with the new name. Well, meet TST, a group under JSL Company which has already changed its name two times. Since their debut on January 1st, 2017, the group has changed the name from 7STONE to Top Secret to now TST. The group currently consists of five members (Ain, K, Wooyoung, Junghoon, and Yonghyeon), after member Yohan’s shockingly sudden death in June 2020.

Are you curious about the group’s story? Scroll down the article below to find out more about them!


TST Group Profile

Previously known as 7STONE and Top Secret, now TST (일급비밀), first made their debut on January 1st, 2017, under JSL Company (now known as KJ Music), with the mini-album Time’s Up with the title track “She.” They first debuted with the name Top Secret in 2017 before changing it to TST in 2018.

The group originally debuted with seven members Ain, K, Wooyoung, Junghoon, Yonghyeon, Yohan, and Kyeongha. But, Kyeongha left the group on June 11th, 2018, due to his sexual assault case, while member Yohan, unfortunately, passed away at the age of 28 on June 16th, 2020.

Now, the group consists of five active members Ain, K, Wooyoung, Junghoon, and Yonghyeon.

Group Information

  • Group name: TST
  • Origin: Seoul, South Korea
  • Genres: K-Pop
  • Years active: 2017–present
  • Debut Date: January 1st, 2017
  • Label(s): KJ Music
  • Current members: Ain, K, Wooyoung, Junghoon, and Yonghyeon
  • Former members: Kyeongha, Yohan
  • Fandom Name: HANA (하나)
  • Official Accounts:
    Twitter: @FS7_official
    Facebook: officialFS7
    Instagram: @fs7official
    Fan Café: Daum Cafe
    YouTube: 일급비밀 TST Official


TST Members’ Profiles and Facts


Ain’s Profile

Stage Name: Ain (아인)
Birth Name: Kim A-in (김아인)
Position: Leader, Main Dancer, Vocalist
Date of Birth: February 15th, 1994
Zodiac Sign: Aquarius
Height: 182 cm (6’0″)
Weight: 64 kg (141 lbs)
Blood Type: O
Twitter: @AIN8008
Instagram: @ainismxx
YouTube (shared with Yohan): YO-I요아이


Ain’s Facts

  • Asan, Chungcheong, South Korea, is his place of birth
  • He didn’t make it when auditioning for JYP Entertainment
  • Choreography is his specialty
  • He used to be a dance teacher before his debut
  • Tonkatsu is his favorite food
  • Red and purple are his favorite colors
  • Wonder Girls, EXO, and Big Bang are his favorite idols
  • He used to be a member of NOM
  • On April 6th, 2020, he enlisted in the military


K’s Profile

Stage Name: K (케이)
Birth Name: Kim Hyeong-in (김형인)
Position: Lead Vocalist
Date of Birth: May 6th, 1991
Zodiac Sign: Taurus
Height: 178 cm (5’10″)
Weight: 63 kg (139 lbs)
Blood Type: AB
Twitter: @ghn5613
Instagram: @kimkei0101


K’s Facts

  • Gwangju, South Korea, is his place of birth
  • He can speak English
  • White is his favorite color
  • When it comes to food, he is not picky since there’s no food he doesn’t like
  • He often has insomnia
  • Super Junior is his favorite idol
  • He used to be a member of NOM
  • He has his own brand called Mellow Wolf
  • A girl with beautiful eyes is his ideal type


Wooyoung’s Profile

Stage Name: Wooyoung (우영)
Birth Name: Choi Woo-yeong (최우영)
Position: Lead Dancer, Vocalist, Rapper
Date of Birth: May 14th, 1996
Zodiac Sign: Taurus
Height: 178 cm (5’10″)
Weight: 60 kg (132 lbs)
Blood Type: A
Instagram: @wy0514


Wooyoung’s Facts

  • Sexy, cute and charming is how he describes himself
  • He can speak English fluently
  • Danny Choi is his English name
  • He’s fluent in English because he studied in California for seven years
  • Korean chicken is his favorite food
  • A bracelet is his good luck charm
  • Due to body discomfort, he is not participating in TST’s 2020 comeback


Junghoon’s Profile

Stage Name: Junghoon (정훈)
Birth Name: Lee Jung-hoon (이정훈)
Position: Rapper
Date of Birth: October 18th, 1996
Zodiac Sign: Libra
Height: 175 cm (5’9″)
Weight: 58 kg (128 lbs)
Blood Type: AB
Instagram: @hoon2_jung


Junghoon’s Facts

  • He is the rapper in the group
  • He participated in KBS2’s The Unit and passed the auditions but was eliminated after the 1st round, where he performed Block B’s “HER”


Yonghyeon’s Profile

Stage Name: Yonghyeon (용현)
Birth Name: Kwon Yong Hyeon (권용현)
Position: Main Vocalist, Maknae
Date of Birth: December 18th, 1996
Zodiac Sign: Sagittarius
Height: 175 cm (5’9″)
Weight: 58 kg (128 lbs)
Blood Type: AB
Instagram: @yyyyyyonggg


Yonghyeon’s Facts

  • He is the main vocalist and maknae of the group
  • He is known to greet fans through his personal Instagram account
  • On his Instagram, he uploads his daily photos, both when doing individual activities and when with TST


The Late Yohan’s Profile

Stage Name: Yohan (요한)
Birth Name: Kim Jung-hwan (김정환)
Position: Vocalist
Date of Birth/Death: April 16th, 1992/June 16th, 2020
Height: Aries
Height: 180 cm (5’11″)
Weight: 64 kg (141 lbs)
Blood Type: O
Twitter: @K_jeonghwan
Instagram: @yohanee0416
YouTube (shared with Ain): YO-I요아이


The Late Yohan’s Facts

  • Ulsan, South Korea, was his place of birth
  • He could play the drums and the piano
  • He was a fan of various boy groups like VIXX, B.A.P, BTOB, and INFINITE
  • Watching movies was his hobby
  • He used to be a member of NOM
  • On June 16th, 2020, it was announced that he passed away at the age of 28 and the cause of his death has not been revealed