Lee Chang-sub

Lee Chang-sub (; born ), better known mononymously as Changsub, is a South Korean singer, musical actor and entertainer. He is a lead vocalist of the South Korean boy group, BtoB.
Biography.
Lee Changsub was born in Suwon, Gyeonggi-do, South Korea. He studied Practical Music at Howon University with BTOB group-mate Lim Hyunsik. They both got admitted in 2011 with a cutthroat 3000:5 ratio at that time.
Prior to his debut as an idol, he won a "Daesang" at the 16th Suwon Music Festival 2008, and even became vice president of Red Cross Youth Gyeonggi Province in 2009.
Military service.
He began his military duty by enlisting as an active duty soldier on January 14, 2019. On July 24, Lee recorded a special single— a new theme song for the ROK Army alongside Shinee's Onew and Key, Exo's Xiumin, Infinite's Kim Sung-kyu, 2AM's Jo Kwon and Jinwoon, Yoon Ji-sung and actors Kim Minseok, and Lee Jae-kyoon.
He was officially discharged on August 21 following the COVID-19 protocol. 
Philanthropy.
On October 21, 2017, Lee Chang-sub visited his alma mater and delivered a scholarship of ₩10 million to his high school alma-mater, Samil Commercial High School. Changsub said, "I couldn't have imagined this when I was in school. It's an honor to be in a situation where I’m able to deliver this scholarship for the younger generation of students. I’ve been able to come this far thanks to my teachers and my school who helped me until the end when I was a student."
Career.
Lee debuted as a lead vocalist of BTOB on March 21, 2012.
Lee has also participated in lyrics composition of some tracks by BTOB including, "Last Day", "Killing Me" and "Melody".
He became a contestant on King of Masked Singer as "Mr. Wifi" in 2015. In 2016, he joined the cast of new season of SBS's reality-documentary show, "Law of the Jungle", which was filmed in Mongolia.
He started his career in musicals in 2017. He was cast in the musical adaptation of "Boys Over Flowers" as the lead, Goo Jun-pyo. He also played a role in the Korean production of the musical "Napoleon" as Lucien, Napoleon's little brother. Next, he was cast as the titular main character in the musical "Edgar Allan Poe".
The following year, he got another leading role as Eddie Birdlace in "Dogfight". His last musical project before military enlistment was "Iron Mask"
On October 27, 2020, Cube announced that they have formed a unit called BtoB 4U consisting Eunkwang, Minhyuk, Changsub and Peniel. The unit debuted on November 16 with their first mini-album, "Inside" and title track "Show Your Love".
Solo.
Lee Changsub was the first member to debut his own solo album called "bpm 82.5" in Japan. With the title track "At The End", this Japan debut in 2017 also marked the first part of the Piece of BTOB, showcasing monthly solo releases from each BTOB member.
In December 2018, he released his first Korean-solo album titled "Mark". He considers it his gift to his fans before enlistment.
He held his first solo concert, "SPACE" last January 4, 5 and 6, 2019 at the Yes24 Live Hall in Gwangjin District, Seoul.