The short, but dramatic life of Korean independence fighter Ahn Jung-geun (1879-1910) has been adopted into various novels and musicals, but the musical “Hero” has been the best-known adaptation with veteran actor Jung Sung-hwa playing Ahn on stage for 14 years since its premiere in 2009.

When megahit film director Youn Je-kyoon watched Jung performing on stage in 2012, it became obvious for Youn to bring the award-winning musical to the big screen.

“If I were to create a film on Ahn Jung-geun, it did not have to be musical, but something like a drama genre. But because I wanted to make a film based on the musical ‘Hero,’ I cried a lot when I first watched it, it had to be a musical film. (The musical) was just so touching for me,” said Youn in a press conference Thursday at CGV Yongsan.

Musical film “Hero” revisits the final year of Ahn, who assassinated Japan’s first resident general of Korea, Ito Hirobumi, at Harbin Station in northern China on Oct. 26, 1909. Five months later, Ahn was executed in a Chinese prison at the age of 34.

As the country’s first film adaptation of the musical, much of the characters’ emotion and dialogue are expressed through the musical numbers.

Empress Myeongseong’s court lady Seolhui, a fictional character played by Kim Go-eun, controls her emotions as she disguises herself as a geisha in front of Ito. But her anger and fear spying for the independence fighters burst out in her solo.

Ahn's mother, Cho Maria, played by veteran actor Na Moon-hee, adds another emotional climax to the movie through the well-loved track “My Loving Son.”

“Even before shooting that scene (with 'My Loving Son') my emotion reached a peak and I could not even start singing because it was too sad. The power of the music really maximized the actors’ performance,” Na told reporters.

With the exception of Jung, the cast comprises nonmusical actors. However, director Youn insisted on singing live on the set instead of lip-syncing in order to deliver clear, genuine emotions and realistic performances on the big screen.

“The difference between the musical and our film is that we are showing the audience what is familiar (the musical numbers) and what is new, such as the storyline of Ahn’s past and detailed scenes that the musical version was unable to express,” said Youn.

Jung, who has won several awards for his charismatic depiction of Ahn Jung-geun on the stage over the past decade, said the film depicts the human side of Ahn, not only the brave, upright hero.

The film sheds light on Ahn as a devoted son and father of three. He even releases prisoners of war after a battle with Japan. Prior to his death sentence, he delivers a missive to a Japanese prison official saying what he had desired was to make a world where each of their children use their hands for praying, not killing each other.

Despite the gravity of the plot, supporting independence fighter roles played by Cho Jae-yoon, Bae Jung-nam, Lee Hyun-woo and Park Jin-joo add excitement to the movie.

“My favorite scene was when independence fighters and extra actors gathered to sing in chorus the famous track ‘Promising the Day.’ We all worked really hard to deliver the emotions while singing and even calling ourselves trainees from ‘JK Academy,’" said Cho, who played Woo Deok-soon, referring to the director's fictional song-and-dance studio.

Bae, who plays Cho Do-seon, a veteran sniper, said he had goosebumps singing together in that scene and noted that the intimacy among the actors came through on the screen.

Park, who forms a romantic relationship with Lee, said the actors were motivated by Jung’s 100 percent integration with Ahn.

Director Youn especially appreciated all the actors singing live on the set despite setbacks and difficulties.

“After deciding on shooting without lip-syncing, I had to cancel numerous OK cuts because of the sound, although acting was good. Despite the cold weather, the staff had to take off their parkas due to the rustle made by the fabric. We also put rugs on the ground and wrapped our shoes with cloth to avoid any noise,” said Youn.

Shooting of the film was completed in 2019, but its release suffered numerous delays due to the pandemic.

After megahit movies “Haeundae” (2009) and “Ode to My Father” (2014), Youn said he hoped to give the audience an opportunity to revisit and better know the relatively lesser-known last year in the life of Ahn, who sacrificed himself for the country.

"Hero" hits theaters Dec. 21.