Yeonjun

Choi Yeon-jun was born on September 13, 1999, in Seongnam, Gyeonggi Province, South Korea. An only child, he spent two years living in the United States during his elementary school years to study English before returning to South Korea. He attended Korean Arts High School and later enrolled in the Broadcasting and Entertainment Department at Global Cyber University.

Before his debut, Yeonjun trained at Cube Entertainment and then joined Big Hit Entertainment in 2014 after auditioning with BTS's "Boy in Luv". During his training at Big Hit, he gained the reputation of being the company's "legendary trainee" because he consistently placed first in monthly evaluations across dance, vocal, and rap categories. In 2014, he also appeared as a background dancer at the Melon Music Awards.

On January 10, 2019, Yeonjun was introduced as the first member of Tomorrow X Together via an introductory film. The group officially debuted on March 4, 2019, with their extended play The Dream Chapter: Star. Yeonjun serves as the oldest member of the group, performing alongside bandmates Soobin, Beomgyu, Taehyun, and HueningKai. He also created the group's official hand gesture.

Beyond performing, Yeonjun has been an active songwriter and composer for the group. His songwriting credits span numerous TXT tracks, including "Fairy of Shampoo", "Maze in the Mirror", "Wishlist", "No Rules", "Frost", "Loser=Lover", "Good Boy Gone Bad", "Happy Fools", and "I'll See You There Tomorrow". In 2022, he teamed up with bandmate Taehyun, American singer Salem Ilese, and Norwegian DJ Alan Walker on the collaborative single "PS5".

Yeonjun began expanding into individual musical projects in 2021 by featuring on the track "Blockbuster" from Enhypen's studio album Dimension: Dilemma. In September 2024, he contributed his first solo drama soundtrack, "Boyfriend", for the series Cinderella at 2 AM, which earned him the OST Popularity Award at the Blue Dragon Series Awards.

On September 19, 2024, Yeonjun made his official solo debut with the hip-hop single "Ggum", earning a music show trophy on Mnet's M Countdown and winning Favorite K-pop Dance Challenge at the 2025 iHeartRadio Music Awards. He went on to release his debut solo extended play, No Labels: Part 01, in November 2025, followed by No Labels: Part 02 in July 2026. He also featured on a remix of Katseye's single "Touch" in October 2024.

Yeonjun has maintained an extensive presence in fashion and television. In 2021, he made his runway debut at New York Fashion Week for the South Korean brand UL:KIN and made a cameo appearance in the television drama series Live On. He served as a regular host for the music program Inkigayo from 2022 to 2024 alongside co-hosts such as Roh Jeong-eui and Seo Bum-june, and later hosted SBS Gayo Daejeon across multiple editions.

In July 2022, he became a brand ambassador and guest creative director for the streetwear label Privé Alliance, releasing a limited capsule collection. In May 2024, Moncler named him a global brand ambassador. Yeonjun later walked the runway for Miu Miu at Paris Fashion Week in March 2026, subsequently being appointed an official Friend of the House for the brand.