Lee Jong-suk and Yoona’s friendship makes them a convincing couple in Big Mouth

The director of Korean crime noir series Big Mouth says the long friendship of its two leading stars – actor Lee Jong-suk and K-pop girl group Girls’ Generation’s Yoona, whose real name is Im Yoon-ah – helped to make them a convincing husband-and-wife duo on-screen.

Oh Choong-hwan, who also helmed hit shows such as the highly acclaimed fantasy series Hotel Del Luna (2019) and workplace drama Start-Up (2020), tells The Straits Times five things to know about Big Mouth, which is available on Disney+.

1. Reuniting with Lee Jong-suk

Oh has only high praise for the actors he cast in the show, including Lee, whom he had worked with on While You Were Sleeping (2017).

Lee, 32, plays Park Chang-ho, an incompetent lawyer nicknamed “Big Mouth”, who gets thrown into jail after he is falsely accused of being a notorious con man.

Oh, who has fond memories of their previous collaboration, says: “Jong-suk really shines when he acts with serious, desperate emotions. I think his attention to detail and level of immersion is unique.

“His character often faces life-and-death scenarios in the series and I was just amazed by how he expressed those emotions and situations through his acting.”

2. Perfect leading lady

Oh reveals that not only was Yoona “perfect” for the role of Ko Mi-ho – Chang-ho’s smart, competent and fiercely supportive wife – she was also Lee’s first choice. 

Oh says: “She has this inexplicable positive energy to her. In tough and hopeless situations, she is someone who brings energy to everyone, and it almost feels like she would solve everything. Her character is similar.”

3. Convincing relationship

Before Lee made his debut as a model and then an actor, he was briefly an idol group trainee, reportedly under SM Entertainment – the talent agency that debuted Girls’ Generation – and has known Yoona for a long time.

Oh says the stars’ early links helped in their performance. 

He recalls: “Since they knew each other from when they were young, it created a very friendly environment on set. Chang-ho and Mi-ho are also long-time friends who become a married couple, so I think their friendship helped with the acting. 

“They express a couple dynamic that shows they have a trust between them borne out of the years they have known each other.”

4. Challenging genre

Big Mouth is the first time Oh is trying his hand at the noir genre, as he was drawn to the appeal of making something darker and grittier in tone. But the project came with its challenges too, especially since many scenes were set in the prison that houses Chang-ho.

“Shooting crowd scenes within the prison grounds involved a lot of people, including the actors and staff moving in large numbers at once. As a director, it’s always a challenge for me to shoot such scenes in an efficient manner.”

5. Secret sauce to good TV

Oh has found success in various genres, from the highly acclaimed fantasy series Hotel Del Luna to the workplace K-drama Start-Up. And he says the key to making good, beloved television is love.

“I think dramas that I don’t enjoy shooting on set, dramas that don’t give me motivation, are hard to succeed. If the creator does not fall in love with the series, I don’t think the viewers would fall in love with it too. 

“So that is always my starting point when going into production: I always try my best to create a show that I can enthusiastically jump into, and something that our cast and crew will fall in love with.”

Big Mouth is available on Disney+.