T.O.P aka Choi Seung-hyun (최승현), born November 4, 1987), better known by his stage name T.O.P (탑), is a South Korean recording artist and actor. Best known as a member of the Korean boy band Big Bang, he has branched out to act in various dramas and films, including I Am Sam, Iris and 71: Into the Fire.
 2005–2006: Big Bang debutPrior to his involvement with YG Entertainment, Choi was an underground rapper and a childhood friend of G-Dragon, another member of Big Bang. G-Dragon stated that the two were "neighborhood friend[s] from middle school" and would often dance and rap together. Although G-Dragon later moved away and the two "became distant", he contacted Choi again when YG Entertainment was scouting for candidates to create a boy band. The pair recorded several demos and sent them to Yang Hyun Suk, CEO of YG Entertainment, who later asked Choi to audition. Choi was initially rejected by the record label, which deemed him too "chubby" to fit the "idealistic version" of an idol. Choi later stated that he "went home and exercised really hard because I wanted to join YG Entertainment." Six months later, he returned for another audition and was signed on. He reportedly lost 20 kg in 40 days.
Choosing the stage name of T.O.P. (Korean: 탑), he became one of the two rappers in the group Big Bang, alongside G-Dragon. The two were paired with four others: Taeyang, Daesung, Seungri and So-1; a documentation of their training was aired to promote them. So-1 was dropped by the record label, and Big Bang made its official debut with five members. Their first album, Since 2007, was a fair success, and included T.O.P.'s first solo song "Big Boy." The group achieved mainstream success with the release of the song "Lie" (Korean: 거짓말; Revised Romanization: Geojitmal) from their 2007 mini-album Always, which topped several charts upon its release. The singles, "Last Farewell" (Korean: 마지막 인사; Revised Romanization: Majimak Insa) from the mini-album Hot Issue and "Day by Day" (Korean: 하루하루; Revised Romanization: Haru Haru) from Stand Up, became chart-toppers as well.
 2007–present: Solo developmentFollowing the release of the band's albums and singles, T.O.P. began working on his solo career. In April 2007, he was featured with fellow Big Bang members Taeyang and G-Dragon on singer Lexy's single "Super Fly" for her album Rush. Later that summer, he appeared as an actor in Red Roc’s "Hello" music video. He later became the first member of Big Bang to venture into acting, starring in the KBS2 drama, I Am Sam,. portraying the school's top fighter, Chae Musin. He also took the role of MC of MBC's Music Core on November 10, 2007, only to resign in April of the following year. In 2008, he collaborated with R&B artist Gummy on the song "I'm Sorry" for her album Comfort, and later with singer Uhm Jung Hwa for her single "D.I.S.C.O." That same year, he was also admitted to Dankook University, to the theater department.
T.O.P later put his solo career on hold while he joined his group for their promotional activities. After more than a year of promoting Big Bang's materials, he returned to acting, playing the assassin Vick in the critically acclaimed Korean television drama Iris. T.O.P. also recorded the song "Hallelujah" for the drama's soundtrack with Taeyang and G-Dragon. Following Iris, T.O.P. and Seungri appeared in the teenage suspense drama, My 19.
T.O.P appeared in the movie 71: Into the Fire which released in June 2010. He received many good critics and praise for his acting; the movie hit 1 million views in a week, making it the first movie of 2010 to reach that number of views in South Korea. He is also in preparation for his solo debut. During Big Bang's Big Show concert in January 2010, T.O.P. performed his new single "Turn It Up." YG Entertainment released a music video teaser for "Turn It Up" on June 14, 2010 which revealed the release date for the full music video to be June 21, 2010. The teaser itself received over 200,000 views within 48 hours of its original posting on YouTube. The official music video was released at noon in South Korea, with over 1,000,000 views and comments in just a few minutes. He is also the first Korean artist to have his song release worldwide on iTunes. On 29 October 2010, he won the Hallyu Popularity Award in the 47th Grand Bell Film Awards.
In November 2010, YG Entertainment announced T.O.P and bandmate G-Dragon would release a collaboration album. Preceding the release of the album, the duo held a world-wide premiere showcase for their album at Times Square in Yeongdeungpo of Seoul, South Korea, which was also broad-casted live on YouTube. To promote their album, the duo released three singles: "High High," "Oh Yeah," and "Knock out." All three singles preceded the release of the album. The singles were commercial successes: "High High" was a chart topper while "Oh Yeah" and "Knock Out" both peaked at #2 and #3 respectively. The album was released on Christmas Eve, and debuted at number one with pre-orders of 200,000 copies.
- GD & TOP (2010)
 Digital singles, collaborations
- "Buckwild" NBK Gray featuring T.O.P.
- "Big Boy"
- "I'm Sorry" Gummy featuring T.O.P
- "All I See Is you" Zia featuring T.O.P
- "As If Nothing's Wrong" (Korean: 아무렇지 않은 척)
- "D.I.S.C.O " (Uhm Jung Hwa featuring T.O.P)
- "Friend" (Korean: 친구; Revised Romanization: Chingu) (T.O.P featuring Tae Yang)
- "Hallelujah" (T.O.P featuring Tae Yang and G-Dragon) (theme song of the drama Iris)
- "Turn It Up"
- "Digital Bounce" Se7en featuring T.O.P
- "Because" T.O.P featuring Seungri (theme song for 19teen)
- Won – 47th Daejong Film Awards for Hallyu Popularity
- Nominated – 47th Daejong Film Awards for Best New Actor
- Nominated – 8th Korea Film Awards for Best New Actor
- Won – Style Icon Awards for Best New Actor
- Won – 31st Blue Dragon Film Awards for Best New Actor
- Won – 31st Blue Dragon Film Awards for Popularity
- Won – Max Movie Award for Best New Actor 
- Nominated – 5th Asian Film Award for Best New Actor
- Won – 47th PaekSang Award for Best New Actor 
- Won – 47th PaekSang Award for Popularity Award (Actor in a Motion Picture)