Youngseo (ALLDAY PROJECT)

Who is Youngseo from ALLDAY PROJECT?

Youngseo is a South Korean singer and lyricist under The Black Label, serving as the main vocalist and maknae of the co-ed group ALLDAY PROJECT. Born Lee Young-seo on November 13, 2005, she stands at 165.5 cm tall and holds blood type A with an ESTJ personality type. Her stage name derives directly from her birth name.

The artist joined Source Music in 2019 and spent four years training with the pre-debut group NTeam. Following postponement of their planned debut, she departed Source Music in 2022. On June 16, 2023, she entered Belift Lab's survival show R U Next? as a contestant. During the show's finale, she ranked 2nd overall, securing her position as a member of ILLIT. Accordingly, she became the second member revealed for the group.

Youngseo terminated her contract with Belift Lab on January 5, 2024, departing from ILLIT before their official debut. In light of her departure, she contacted The Black Label through Instagram direct message, leading to an individual audition that she successfully passed. On June 6, 2025, The Black Label announced her signing and forthcoming debut with their upcoming co-ed group. She was revealed as an ALLDAY PROJECT member on June 9, 2025.

The group released their debut single album "Famous" on June 23, 2025, marking her official entry into the industry. As the youngest member, she holds dual positions as vocalist and maknae within ALLDAY PROJECT. Her training background spans multiple entertainment companies, including SM Entertainment, ADOR, Source Music, and Belift Lab, accumulating approximately four to five years of preparation before her debut. She was the final member to join both The Black Label and ALLDAY PROJECT.

Youngseo's career timeline and journey to ALLDAY PROJECT

Source Music and NTeam training period

Her entertainment industry journey began in 2019 when she joined Source Music and commenced training with the pre-debut group NTeam, dedicating four years to intensive preparation. Prior to Source Music, she had been a trainee at SM Entertainment starting in 2018. During her time at Source Music, she was considered part of the lineup for the agency's planned new group, later known as NewJeans, and spent approximately one year training alongside the eventual debut members while residing in the company dormitory. Following postponement of the NTeam debut plans, she departed Source Music in 2022.

R U Next? survival show appearance

On June 16, 2023, Belift Lab introduced her as a contestant on their girl group survival show R U Next?. Throughout the competition, she demonstrated consistent performance capabilities alongside other former Source Music trainees who had transferred to Belift Lab around 2021. During the show's finale on September 1, 2023, she secured second place in the final rankings, earning her a position in the debut lineup.

ILLIT formation and departure

Belift Lab and Youngseo reached a mutual agreement to terminate her exclusive contract on January 5, 2024. The company's official statement requested the public to refrain from speculation regarding the development, noting the decision reflected consideration for the artist's wishes. Following her departure, numerous rumors emerged suggesting her potential inclusion in various upcoming group debuts, requiring her to maintain a low profile. She revealed concerns about being too old to debut at 19 years of age, despite industry standards.

Joining The Black Label and ALLDAY PROJECT debut

She contacted The Black Label through Instagram direct messages, submitting performance clips and successfully passing an individual audition. The Black Label announced her signing on June 6, 2025, confirming her forthcoming debut with their co-ed group. She revealed her membership in ALLDAY PROJECT on June 9, 2025, with the group subsequently debuting through their single album "Famous" on June 23, 2025.

Youngseo's age, height, and basic profile information

Lee Young-seo originates from Seodaemun-gu, a district in Seoul, South Korea, where she was born on November 13, 2005. Her birthdate places her under the Scorpio zodiac sign, while her Chinese zodiac corresponds to the Rooster. She holds Korean nationality and represents the color purple within ALLDAY PROJECT.

Her educational background includes attendance at Kyonggi Elementary School, where she was notably cast for entertainment training in front of the school premises. She subsequently enrolled at Gaepo High School for her secondary education. The casting opportunity at her elementary school marked the initial entry point into her trainee period.

Height measurements for the artist range between 165 cm and 166 cm according to different profile sources, with one source specifying 165.5 cm (5'5"). These variations reflect typical differences in measurement reporting across entertainment databases. Her physical profile also includes blood type A.

Personality assessments identify her MBTI type as ESTJ, categorizing her within the Extraverted, Sensing, Thinking, and Judging personality framework. This classification suggests traits associated with organizational capabilities and direct communication patterns.

The stage name "Youngseo" (영서) derives directly from her Korean birth name without modification. Her full Korean name, Lee Young-seo (이영서), maintains the same pronunciation and written form as her professional identity. She was cast into the entertainment industry through street casting, a common recruitment method in South Korean entertainment where talent scouts identify potential trainees in public locations. Following her initial casting, she accumulated four to five years of training experience across multiple entertainment companies before joining The Black Label.

Youngseo's position and role as ALLDAY PROJECT maknae

Within ALLDAY PROJECT, she holds the positions of vocalist and maknae. Various sources identify her more specifically as the main vocalist, reflecting her primary responsibility for vocal delivery within the group's musical arrangements. She functions as the only consistently stable vocalist in ALLDAY PROJECT at present, with industry discussions noting the other members possess singing capabilities that require additional training and confidence development.

Vocal abilities and style

Her vocal approach demonstrates emotional delivery and vocal strength, characteristics that distinguish her contributions to the group's recordings. She looks up to SZA vocally while maintaining appreciation for multiple female artists, with Billie Eilish serving as her overall role model. Fans of 2NE1 include her among their supporter base. The designation as the only trained vocalist within the lineup reflects her extensive preparation period across multiple entertainment companies before joining The Black Label.

Dance and performance skills

Observations comparing her performances between R U Next? and ALLDAY PROJECT indicate differences in energy output and stage presence. During the survival show, her performances featured what viewers described as a bold aura and determination to prove herself. In contrast, her ALLDAY PROJECT performances appear more relaxed, with some attributing this shift to the group's laid-back performance style rather than capability limitations. The co-ed group operates with less emphasis on powerful choreography compared to typical K-pop formations, resulting in a cohesive presentation where members intentionally moderate their output.

Songwriting credits

Her songwriting involvement spans multiple tracks from ALLDAY PROJECT's debut release. She received writing credits for "Famous" and "Wicked" from the album 'Famous'. Additionally, she contributed to "You And I" from the album 'Look At Me', demonstrating consistent participation in the group's creative process beyond performance duties.

Youngseo's personality, interests, and friendships

MBTI and personality traits

Her MBTI classification identifies as ESTJ, reflecting characteristics associated with extraverted, sensing, thinking, and judging functions. She describes herself as detail-oriented and honest, traits that others characterize as contributing to her skillful approach. Her personal motto states "Let's enjoy everything I do", a philosophy she applies to avoid regret about past events. She exhibits habitual behaviors including frequently touching her hair and saying "Wow". Accordingly, she operates slowly in most activities except eating, where she demonstrates unusual speed and gains energy from the act.

Personal interests and hobbies

Pink serves as her favorite color, while fat macarons represent her preferred dessert. Her favorite animal is cats, with fans assigning her the nickname "Meow-seo" in reference to this preference. She enjoys eating and particularly loves cheese, especially cheddar varieties. Cherries rank among her liked fruits. Her hobby involves making bead rings, a craft-based activity. She wakes around 3-4 PM on days off and feels most comfortable in bed.

Relationships with ILLIT members and other idols

She maintains close relationships with all ILLIT members, with Iroha identified as her best friend. In addition to ILLIT connections, she shares friendships with izna's Bang Jeemin and Jihyun. Her friendship with Jeemin originated during their Source Music trainee period as fellow 2005-born trainees, often sharing restaurant meals before practice. She developed connections with NewJeans members during their year together in shared dormitory arrangements.