Allow them to introduce themselves...
T-ara (also known as Tiara or 티아라) is a 6-member girl group out of Core Contents Media. The same entertainment agency in which artists like Davichi and SG Wannabe are in. T-ara debuted on July 29th 2009 on MBC's 'Golden Fishery', they are the first group to debut on a variety TV show. T-ara's members are Eunjeong (the leader), Hyomin, Jiyeon, Soyeon, Qri, and Boram.
Before the 6-member T-ara, T-ara was a 5-member girl group. Early June 2009 two months before the girls' official debut, former leader Jiae and member Jiwon quit the group. They believed that the concept of T-ara did not match them. Immediately after, Jeon Boram, the daughter of Jeon Youngrok was added into T-ara. Three weeks before T-ara's official debut, Soyeon and Qri were added into T-ara. Thus making T-ara a 6-member girl group.
[credit: Soompi]Edit:It was announced on July 2010 that T-ara will be adding a 7th member, Ryu Hwa Young, to their group. Also, leadership has changed from Eunjung to Boram by Core Contents Media's idea of having a yearly leadership rotation in order to give every member an opportunity to shine. This "Reborn T-ara" is set to make a comeback in September 2010 with a 2nd album.

Eunjung (은정)    * 
Birth Name: Ham Eunjung (함은정)
    * 
Date of birth: December 12, 1988 (1988-12-12) (age 21)
    * 
Height: 167cm
    * 
Position: Main Vocalist, Main Rapper
    * 
School: DongGook University - Performing arts
    * 
Hobby: Movie, Fashion magazines, Reading
    * 
Specialty: Tae Kwon Do, PanSoRi (Korean traditional narrative song), Horse riding
    * 
Cyworld: http://www.cyworld.com/cong1212    * 
Trivia:           o Original member of T-ara
          o Leader from Debut to July 2010
          o was a child actress prior to T-ara
          o nicknamed 
Jam (sleep) Eunjung for being able to sleep anytime, anywhere
          o Rooms with Soyeon
    * 
Notable Works:          o Appeared in F.T. Island's "Love Sick" and "Thunder" and "Only One Person" MVs.
          o Appeared in SG Wannabe's "Gashiri" MV
          o Appeared in Bobby Kim's "Sorry" MV
          o Starred/cameo in dramas: "Toji, the Land" (2004), "Princess Hours" (2006), "God of Study" (2009)
          o Starred/cameo in movies: "Madeleine" (2002), "Beast & Beauty" (2005), "Ice Bar" (2006), "The World of Silence" (2006), "Gosa (Death Bell)" (2008), White (2010)
          o Participated in the T.T.L (Time to Love) project with Supernova
          o Participated in "Wonder Woman" (2009) single with Seeya and Davichi.
          o played the lead role in drama "Coffee House" (2010)
          o Appeared in Davichi's "Time, Please Stop" MV

Hyomin (효민)    * 
Birth Name: Park Sun-young (박선영)
    * 
Date of birth: May 30, 1989 (1989-05-30) (age 20)
    * 
Height: 167cm
    * 
Position: Lead Vocalist, Lead Rapper, Main dancer
    * 
School: SeongGyunGwan University - Acting arts
    * 
Hobby: Photography, Cooking, Drawing, Styling
    * 
Specialty: Musical, Sports, Acting
    * 
Cyworld: http://www.cyworld.com/wwww89    * 
Trivia:           o Original member of T-ara
          o Resembles SNSD's Jessica
          o Was a model and ulzzang
          o Rooms with Jiyeon and Hwa Young
          o her valuable possession are her cameras
    * 
Notable Works:           o Starred in FT Island's "Heaven" MV
          o Starred in SG Wannabe's "Unforgettable Breakup" MV
          o Featured in SS501's "Unlock" MV
          o Participated in the T.T.L (Time to Love) project with Supernova
          o Regular cast member of G7 of KBS2TV's variety show "Invincible Youth"
          o Participated in "Wonder Woman" single with Seeya and Davichi.
          o Cameo in drama "God of Study" (2009) with T-ara
          o was a guest rapper for the following artists: Seeya "Gani", Jerry "Going to Love", Sook Hee "One Love"
          o to make her acting debut in drama "My Girlfriend is a Nine Tailed Fox" (2010)

Soyeon (소연)    * 
Birth Name: Park Soyeon (박소연), formerly Park In-Jung (박인정)
    * 
Date of birth: October 5, 1987 (1987-10-05) (age 22)
    * 
Height: 163 cm
    * 
Position: Lead Vocalist
    * 
Trivia:          o One of the 3 new members that replaced original members Jiwon and Jiae
          o Won Gold in 2005 CMB ChinChin Music Festival competition.
          o Former SM Entertainment Trainee
          o One of the 11 trainees who trained to be in 
Girls' Generation, however quit due to personal reason.
          o Rooms with Eunjung
          o calls herself "Mirror Prince" because she always carries a hand mirror around
          o Is a close friend of MBLAQ's Seungho
    * 
Notable Works:          o Starred in variety show "Invincible Baseball" (2009)
          o Participated in the T.T.L (Time to Love) project with Supernova
          o Cameo in drama "God of Study" (2009) with T-ara
          o Cameo in drama "Giant" (2010) with Q-ri
          o Released a single [w/ Ock Ju Hyun] for Coffee House OST
          o Released a single "What Should We Finish?" for Death Bell 2 OST

Boram (보람)    * 
Birth name: Jeon Boram (전보람)
    * 
Date of birth: March 22, 1986 (1986-03-22) (age 24)
    * 
Height: 155cm
    * 
Position: Leader (July 2010 - current), Sub Vocalist
    * 
Cyworld: http://www.cyworld.com/fromlaboheme    * 
Trivia:          o First of the 3 new members added to replaced original members Jiwon and Jiae
          o Father is singer Jeon Young-rok and mother is actress Lee Mi-young, late grandmother singer Baek Sul Hee
          o Oldest and shortest member in T-ara
          o Was a solo artist prior to her addition to T-ara
          o Was mistaken for an elementary school kid by Jiyeon
          o Loves to eat food
          o Rooms with Qri
    * 
Notable Works:          o Starred in Kebee's "Feeling You" MV
          o Released digital single Is it today? from Lucifer Project Vol.1 Love (2008.04.15)
          o Released single From Memory (2008.11.14)
          o Appeared in drama "Hon (Soul)" (2009) with fellow member Jiyeon.
          o Cameo in drama "God of Study" with T-ara.
          o Appeared in "Tik Tok" music drama Cass Beer CF with 2PM & Yoon Eun Hye.

Q-ri (큐리)    * 
Birth name: Lee Ji-hyun (이지현)
    * 
Date of birth: December 12, 1986 (1986-12-12) (age 23)
    * 
Height: 162cm
    * 
Position: Sub Vocalist
    * 
Cyworld: http://www.cyworld.com/dodoljh    * 
School: MyunJi University - studying theatrics
    * 
Trivia:          o One of the 3 new members that replaced original members Jiwon and Jiae
          o Her stage name Qri is a combination of the words "
Cutie & P
retty"
          o Easy to identify her with her cute beauty mark on her nose
          o Was an ulzzang and model
          o Shares the same birthday with Eunjung
          o Rooms with Boram
    * 
Notable Works:          o Appeared in drama "Queen Seon Deok"
          o Cameo in drama "God of Study" with T-ara
          o To make acting debut as a lead in a drama (Untitled) (2010)

Jiyeon (지연)    * 
Birth Name: Park Ji-yeon (박지연)
    * 
Date of birth: June 7, 1993 (1993-06-07) (age 17)
    * 
Height: 167cm
    * 
Position: Sub Vocalist
    * 
School: HyeHwa Girls High School
    * 
Hobby: Sleeping, Movies
    * 
Specialty: Sports, cooking
    * 
Cyworld: http://www.cyworld.com/Park4471    * 
Trivia:          o Original member of T-ara
          o Sometimes labeled as "Little Kim Tae Hee" for resembling the actress
          o Rooms with Hyomin and Hwa Young
          o She was a model during pre-debut years
    * 
Notable Works:          o Starred in SG Wannabe's "My Lovely Cry Baby" MV
          o Starred in dramas "Soul" and "God of Study"
          o Release a single "Rolling" for "God of Study" OST
          o Participated in the T.T.L (Time to Love) project with Supernova
          o Participated in "Women's Generation" single with Seeya and Davichi.
          o Cameo/starred in "High Kick Through The Roof" and "Aeja’s Older Sister, Minja"
          o Cast for "Death Bell 2"  (2010)
          o Cast member on variety show "Heroes"


(Left: Hwa Young, Right: Twin sister Hyo Young) 
Hwa Young (화영)    * 
Birth Name: Ryu Hwa Young (류화영)
    * 
Date of birth: 1993? age 17
    * 
Height: 168cm
    * 
Position: Sub Vocalist
    * 
Trivia:          o Was added to T-ara July 2010
          o Youngest member in T-ara
          o Has a twin sister, Ryu Hyo Young, who will debut in the group Co.Ed
          o Was first discovered with her sister on their appearance on Star King in May 2010
          o previously modeled for an online shopping mall
Former Members
Ji-ae and Jiwon
Ji-ae (지애)    * 
Birth Name: Lee Ji-ae (이지애)
    * 
Date of birth: August 6, 1987 (1987-08-06) (age 22)
    * 
Position: Leader, Main Vocalist
Jiwon (지원)    * 
Birth Name: Yang Ji-won (양지원)
    * 
Date of birth: April 5, 1988 (1988-04-05) (age 21)
    * 
Position: Vocalist
          o Featured in 'Death Bell'
          o Good Entertainment Trainee before entering T-ara
          o Featured in 'A Story Sadder Than Sadness'
          o Was part of the defunct group "5Girls" with Yubin (Wonder Girls), UEE (After School), Hyosung (Secret), and Cube ent. singer Choi Jina (G.NA)
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credits: wiki, soompi, tiaradiadem