A man who refused to give up his seat on an overbooked United Airlines flight, leading to his being dragged off the plane on Monday has been identified as a popular artist in Vietnam before moving to the U.S.

Video showing the passenger, identified as Vietnamese-American doctor David Dao, being yanked from his seat by airport security and dragged from United Airlines Flight 3411 at Chicago O'Hare International Airport went viral and sparked global outrage.

Some Vietnamese sources were quick to realize that Dr. Dao is Dao Duy Anh, a well-known singer and songwriter in Ho Chi Minh City back in the pre-1975 period.

Reuters cited information from Kentucky's medical board website as saying that doctor David Dao graduated in 1974 in Ho Chi Minh City before leaving for the U.S. around one year later.

Initial media reports mistook him as a Chinese passenger.

A doctor with music talent

Nguyen Thuy Hoan, a seasoned music teacher who currently chairs a traditional music club in the southern Vietnamese city, has confirmed that it was one of her old students who is in the viral video seen by millions around the world.

Hoan told Tuoi Tre (Youth) newspaper on Wednesday that doctor-composer Dao Duy Anh was among her students at the erstwhile Saigon National Music School before 1975.

Duy Anh was the founder of the Bach Viet Band around 50 years ago. The band consisted of engineering, medical, pharmacy and dentistry students who were also students at the Saigon National Music School, Hoan said.

One of the Bach Viet members, composer Tran Bo, also told Tuoi Tre more about the musical career of Dao Duy Anh, as well as his contribution to the Vietnamese traditional music, before he moved to the U.S. and became a doctor there.

Speaking from Ho Chi Minh City, Bo said Duy Anh was known as one of the most talented members of Bach Viet, which was founded with a goal to write and perform songs under Vietnam’s traditional and folk styles.

The band thus only used traditional musical instruments, with Duy Anh mastering zither and dan nhi – a Vietnamese bowed string instrument with two strings, according to Bo.

Some other Bach Viet members have also become well-known singers or composers in the 1980s and 1990s, such as Y Vu, Dinh Van or Nhat Sinh.

Dr. Dao, as a talent songwriter back in Vietnam, is the author of two folk-themed songs, Tat Nuoc Dau Dinh and Ta Ve Ta Tam Ao Ta, Bo revealed.

The revelation has taken many by surprise as these songs have been favored in the country for decades yet few have known of their author.

Duy Anh won the top prize of a music competition with Ta Ve Ta Tam Ao Ta in the pre-1975 period, Bo said, while excusing that he could not remember the exact name of the contest due to old age.

Composer Bo asserted that Bach Viet, despite being an amateur music band, had contributed greatly to the pre-development stage of contemporary Vietnamese music by pioneering in combining traditional with modern musical instruments in their works.

In 1984, Bach Viet was chosen to represent the youth in southern Vietnam at an event to mark the 30^th anniversary of the Dien Bien Phu Victory in the northern province of Dien Bien.

In 2015, Tran Bo, several Bach Viet members and Dao Duy Anh had two performances, singing the doctor-composer’s songs, in the Orange County and San Jose to celebrate the 45^th founding anniversary of the band.