TST Members Profile and Facts
TST (일급비밀), formerly known as 7STONE (세븐스톤) and TopSecret (일급비밀), was a South Korean boy group under KJ Music Entertainment (previously known as JSL Company), with its latest lineup consisting of 4 members: Ain, K, Wooyoung, and Yonghyeon. The group was first introduced in February 2016 as 7STONE, with 7 members: Ain, K, Wooyoung, Yonghyeon, Yohan, Junghoon, and Kyeongha. On March 5 of the same year, they began promotions in Japan and changed their name to TopSecret. The group officially debuted on January 1, 2017, with the mini album Time’s Up. On April 3, 2018, they rebranded once more to TST. The group quietly disbanded at the end of 2020 following a period of inactivity.
Group Name Meaning: TST is the abbreviation of their previous name, TopSecret.
Official Greeting: “TST, shh! Hello, we are TST!” (TST, 쉿! 안녕하세요, 일급비밀입니다!)
TST Official Fandom Name: HANA (하나)
Fandom Name Meaning: It means “one” in Korean, symbolizing that the members and fans are one-of-a-kind to each other.
TST Official Color(s): N/A
Official SNS:
X: @FS7_official/ @TS7_official/ @FS7_JAPAN
Instagram: @fs7official
Facebook: officialFS7
Fan Cafe: FS7official
YouTube: 일급비밀 TST Official
TST Member Profiles:
Ain
Stage Name: Ain (아인)
Birth Name: Kim A In (김아인)
Position(s): Leader, Main Dancer, Vocalist
Birthday: February 15, 1994
Zodiac Sign: Aquarius
Chinese Zodiac Sign: Dog
Height: 182 cm (6’0″)
Weight: 64 kg (141 lbs)
Blood Type: O
MBTI Type: N/A
Nationality: Korean
Instagram: @ainismxx/ @yoio505 (With Yohan)
X: @AIN8008
Youtube: 아인스크림 Ain’scream/ YO-I요아이 (With Yohan)
Ain Facts:
– He was born in Asan, Chungcheong, South Korea.
– He’s currently a member of EPIC TRAVELS (2024-present).
– Ain is a former member of NOM (2013-2016).
– He participated in the dance competition Be Mbitious (2022).
– He completed his military service as part of the military band from April 6, 2020, to October 12, 2021.
– Ain auditioned for JYP Entertainment, though he was not selected.
– Before debuting as an idol and after TST disbanded he worked as a dance instructor and held dance workshops in Korea and overseas.
– He won the Grand Prize at a National Youth Dance Contest and the Mnet Dream Project Dance Division Championship.
– He runs a YouTube channel and Instagram account called YO-I together with Yohan, which he still keeps active to this day.
– Education: Incheon Shinjeong Middle School, Incheon Posco High School, Global Cyber University (Department of Broadcasting and Entertainment)
– He has a younger sister.
– He’s close with Dancing 9’s Kim Solhee.
– Ain served in the military alongside INFINITE‘s Sungkyu and Feeldog.
– He’s a fan of EXO, BIGBANG, and Wonder Girls, with his bias being Yeeun.
– He became an idol because it allows him to freely express his passions for singing, dancing, and choreography, and he feels that the version of himself on stage is the most authentic.
– His hobbies are playing badminton and basketball.
– His specialties are creating choreographies, his leadership skills, and running.
– He’s atheist.
– A singer he looks up to is Park Jinyoung (JYP), as he’s a fan of his music style.
– His favorite movie genre is action.
– His favorite foods are tonkatsu and ice cream, especially blueberry and cheese flavor.
– Ain’s favorite colors are red and purple.
– He isn’t a big fan of marshmallows and animals.
– His ideal type is a cool, tough, calm, and open-minded girl.
K
Stage Name: K (케이)
Birth Name: Kim Hyeong In (김형인)
Position(s): Lead Vocalist
Birthday: May 6, 1991
Zodiac Sign: Taurus
Chinese Zodiac Sign: Goat
Height: 178 cm (5’10″)
Weight: 63 kg (139 lbs)
Blood Type: AB
MBTI Type: N/A
Nationality: Korean
Instagram: @seo_yuan
X: @ghn5613
Youtube: Klog
K Facts:
– He was born in Gwangju, South Korea.
– He has an older brother.
– He speaks English.
– His favorite color is white.
– He is not picky when it comes to food. There’s no food he doesn’t like.
– His favorite food is corn.
– He loves shopping.
– He can knit.
– He often has insomnia.
– The reason why he became a singer is because he feels excited when he’s on stage and that he loves music and dancing too much, he cannot hide it.
– He’s a fan of Super Junior.
– He is a former member of NOM.
– K has his own brand called Mellow Wolf.
– K enlisted in the military on March 21, 2019. He was discharged on January 14, 2021.
– He made his solo debut on April 10, 2021, with the digital single ‘Missing You’.
– K and U-kiss Member Kiseop have created a restaurant named ‘으악생’. (CR Nugupromo on X)
– On December 29, 2024, Seo Yuan got married to his girlfriend, Kang Su-hyeon.
– He and his wife welcomed their 1st son on April 4, 2025.
– K’s ideal type: is a girl with beautiful eyes.
Wooyoung
Stage Name: Wooyoung (우영)
Birth Name: Choi Woo Yeong (최우영)
English Name: Danny Choi
Position(s): Lead Dancer, Vocalist, Rapper
Birthday: May 14, 1996
Zodiac Sign: Taurus
Chinese Zodiac Sign: Rat
Height: 178 cm (5’10″)
Weight: 60 kg (132 lbs)
Blood Type: A
MBTI Type: N/A
Nationality: Korean
Instagram: @wy0514
Wooyoung Facts:
– He was born in Seoul, South Korea.
– In 2019 he went on hiatus citing “health issues”, and would remain inactive until the group’s disbandment.
– In 2024 he was convicted of illegally filming multiple sexual partners on more than 23 occasions and was sentenced to 1 year and 4 months in prison, 40 hours of a sexual violence treatment program, and a 3-year employment restriction.
– He is a former pre-debut member of HIGHEND (2015).
– He studied in California for 7 years and is fluent in English.
– Wooyoung has an older brother.
– He can both sing and rap.
– His role model is G-DRAGON.
– His specialties are ballads, speaking English, and doing voice impressions of G-DRAGON, Yoon Munsik, and P-Type.
– He loves playing basketball.
– His favorite food is Korean chicken.
– His lucky charm is a bracelet that he always wears.
– He describes himself as sexy, cute, and charming.
Yonghyeon
Stage Name: Yonghyeon (용현)
Birth Name: Kwon Yong Hyeon (권용현)
Position(s): Main Vocalist, Maknae
Birthday: December 18, 1996
Zodiac Sign: Sagittarius
Chinese Zodiac Sign: Rat
Height: 175 cm (5’9″)
Weight: 58 kg (128 lbs)
Blood Type: AB
MBTI Type: INTJ
Nationality: Korean
Instagram: @uo.home
X: @yyyyyyonggg_
Yonghyeon Facts:
– He was born in Busan, South Korea.
– He’s currently a member of XD (2023-2024) under the stage name UO (유오).
– Yonghyeon participated in PROJECT 7 (2024).
– He debuted as a soloist on April 6, 2023, with the single album Restart.
– He sang the OSTs “기다릴게” and “Wake Up” for the BL Ball Boy Tactics.
– Yonghyeon featured on WOONIE‘s “Want” and “Up All Night”, KissN‘s “환승연애”, and DCaffeine‘s “Love Confession”.
– He took part in the writing and composition of “Up All Night”, “Love Confession”, and all of his solo releases.
– Education: Global Cyber University (Broadcast Entertainment Bachelor, graduated)
– He has many idol friends, including former 14U‘s Gyeongtae, ATEEZ‘s Wooyoung, and former VI’ENX‘s Uin.
– He has an older sister.
– His role model is TVXQ, who inspired him to become an idol.
– His hobby is working out.
– Yonghyeon’s specialties are lyric writing and composition.
– His favorite music genre is R&B
– He considers his charming point to be his live stages.
See more Yonghyeon facts…
Member for Eternity:
Yohan
Stage Name: Yohan (요한)
Birth Name: Kim Jeong Hwan (김정환)
Position(s): Vocalist
Birthday: April 16, 1992
Zodiac Sign: Aries
Chinese Zodiac Sign: Monkey
Height: 180 cm (5’11″)
Weight: 64 kg (141 lbs)
Blood Type: O
MBTI Type: N/A
Nationality: Korean
Instagram: @yohanee0416/ @yoio505 (With Ain)
X: @K_jeonghwan
YouTube: YO-I요아이 (With Ain)
Yohan Facts:
– He was born in Ulsan, South Korea.
– On June 16, 2020 it was announced that Yohan unfortunately passed away on the 14th, at age 28. The cause of death wasn’t revealed.
– He’s a former member of NOM (2013-2016).
– He runs a YouTube channel and Instagram account called YO-I together with Ain.
– He can play the drums and the piano.
– He’s a fan of various boy groups like Vixx, B.A.P, BTOB, INFINITE
– His hobby is watching movies.
– He is not a good swimmer.
– He likes animals.
– He can beatbox and play the piano.
– According to Ain, Yohan is the best cook in the group
Former Members:
Junghoon
Stage Name: Junghoon (정훈)
Birth Name: Lee Jung Hoon (이정훈)
Position(s): Rapper
Birthday: October 18, 1996
Zodiac Sign: Libra
Chinese Zodiac Sign: Rat
Height: 175 cm (5’9″)
Weight: 58 kg (128 lbs)
Blood Type: AB
MBTI Type: N/A
Nationality: Korean
Instagram: @hoon2_jung
Junghoon Facts:
– Junghoon participated on “The Unit” and passed the auditions but was eliminated after the 1st round, where he performed Block B’s “HER”.
– On October 16, 2020 he announced that he left TST and he opened a Youtube channel (HoonheeTV) with his girlfriend.
Kyeongha
Stage Name: Kyeongha (경하)
Birth Name: Lee Kyeong Ha (이경하)
Position(s): Rapper, Maknae
Birthday: August 3, 1998
Zodiac Sign: Leo
Chinese Zodiac Sign: Tiger
Height: 174 cm (5’9″)
Weight: 57 kg (126 lbs)
Blood Type: O
MBTI Type: N/A
Nationality: Korean
Instagram @of.kh_l
Kyeongha Facts:
– Kyeongha participated on “The Unit” and passed the auditions but was eliminated after the 1st round, where he performed Seventeen’s ‘Boom Boom’.
– Kyeongha made friends with Topp Doggs B-Joo while they were in the ‘Boom Boom’ team.
– In May 2018, Kyungha was sentenced to 18 months in jail and 3 years of probation after confessing to sexual harassment charges that occurred in 2014.
– On May 11, 2018 it was announced that Kyeongha is leaving the band because he doesn’t want to harm his group, who were suffering due to their promotions being suspended.
– Kyeongha’s ideal type is someone like Apink’s Son Na-Eun “Lovely image but has a boyish charm at the same time”.
Note: More facts to be added once they are available.
(Special thanks to ~Kratos~, Shain, ~Kookie, Adlea, Markiemin, ninetailgumiho, Elina, m i n e l l e, Hye ♡, Markiemin, Ka-ching, SAAY, TSTgurl, arii, xoyeolfiexo, suga.topia, ~Yume~, Morgan, ↬sadistic.banana, Hirakocchi, vero, chelseappotter, martinka, Chrissi Harder, martinka, Aden M., wakeywakey_leo)
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Who is your TST bias? Do you know more facts about them? Feel free to comment below. It can help new fans find more info about them. 🙂
