On a recent YouTube interview for Park Eun Ha’s Exchange, IU opened up about a surprising moment on set with her When Life Gives You Tangerines co-star Park Bo Gum—one that left a lasting impression on her.

IU, who worked closely with Park Bo Gum during the series’ year-long shoot, shared that while he’s widely known for his warm personality and positive energy, there was a rare moment when he set aside his signature smile to take on the role of a gentle yet firm adult.

“There was one moment that really showed me what kind of person Bo Gum is,” IU recalled. “He’s not only kind, but principled. No matter how unwell he was during filming, he always told everyone he was fine and kept the mood up. But this one time, I saw him speak without smiling.”

That moment came when a young child actor on set repeated a slang word—one that wasn’t terribly offensive, but still inappropriate. IU said it seemed like the child had picked it up somewhere without knowing its meaning.

Park Bo Gum’s reaction was calm and composed. “He gently placed his hands on the child’s shoulders and asked, ‘Do you know what that word means? Promise me you won’t say that again, okay?’” IU said, smiling at the memory. “It really left an impression on me.”

IU and the show’s host both praised Park Bo Gum for stepping in so gracefully—offering correction without shaming, and truly embodying what it means to be a dependable adult.

“Watching him fulfill that role made me admire him even more,” IU shared. “The child actor immediately promised not to say the word again, and it was such a sweet moment. It showed me how sure and grounded Bo Gum really is—and I appreciated that so much.”