IU and Lee Yeon appeared on the YouTube channel 'Cosmopolitan Korea' and shared stories from their time together as well as moments when they were moved by each other.

IU and Lee Yeon revealed that they recently went on a 2-day, 1-night trip to Jeju Island with their co-star Yoo Subin, who is also appearing in the drama '21st Century Great Madam.' They said they climbed a oreum, filmed challenge videos, and enjoyed flower viewing together during the trip. They also shared an experience when the three of them were walking in a park and saw cherry blossoms in full bloom on the day Yoo Subin appeared on 'I Live Alone.'

Regarding the schedule of climbing the oreum during the Jeju trip, IU said, "We said we would take a light walk, but I didn't know it was a course that takes an hour and a half, so I was tricked into going and coming back," and Lee Yeon recalled, "It was very physically demanding." The two exchanged opinions about the oreum walk time, saying "Two and a half hours?" and "An hour and a half," which made them laugh. IU mentioned that filming the challenge was more exhausting than climbing the oreum.

When asked about the chemistry score with the cast, IU gave 98 points and explained, "Because 100 points would be too unrealistic." Lee Yeon added that the Jeju trip proved the good atmosphere on set.

In response to the question about moments when they were moved by each other, Lee Yeon shared a kind story about IU. Lee Yeon said, "When I stayed at Senior Ji-eun's house, even though it wasn't the time IU usually wakes up, she got up before me and prepared fruits and sweet potatoes. She said, 'Eat,' and went back to sleep. It was very touching." She added, "She peeled and prepared apples, blueberries, and sweet potatoes." In response, IU praised Lee Yeon, saying, "Even though she was a guest, Lee Yeon washed the dishes at the speed of light and organized the pajamas and towels she wore like a hotel."

Meanwhile, the MBC drama '21st Century Great Madam,' starring IU and Lee Yeon, is set in a constitutional monarchy Korea and depicts a romance overcoming social status differences.