Kim Woo Bin returned to the film industry in 2019 after a 6-year hiatus due to battling nasopharyngeal cancer. In December 2021, he began filming for the Netflix drama 'Black Knight.' Given his recent health struggles, there were expected difficulties as his role in the drama required him to portray a smoker.

To ensure Kim Woo Bin's well-being, the director, Cho Eui Seok, took special care of the actor's health. In an interview with News 1, Director Cho revealed that all of Kim Woo Bin's smoking scenes were created using computer graphics (CG). He suggested using stunt doubles for Kim Woo Bin's action scenes due to his limited physical strength, but the actor insisted on doing the action scenes himself.

Director Cho explained that the decision to use CG for the smoking scenes was necessary. The original webtoon depicted the character constantly smoking, and omitting this element would have ruined the vibe they wanted for the character. Therefore, the cigarette scenes were entirely generated using CG.

It's important to recognize that CG work can be both time-consuming and costly. This might account for the lengthy period between the completion of filming for 'Black Knight' in May 2022 and its release, as nearly a year was dedicated to post-production. The production budget for the six episodes reached a significant 25 billion KRW (18.7 million USD).

Nevertheless, Director Cho's thoughtful decision to use CG to accommodate Kim Woo Bin's situation has been met with much appreciation and praise from many people.