IU and Byeon Woo-seok reunited in a project after 10 years and shared behind-the-scenes stories from their past filming.

On the 22nd, the two appeared on the YouTube channel 'Youin Radio' and expressed their feelings about reuniting as lead actors in MBC's Friday-Saturday drama '21st Century Grand Lady.' At this event, IU and Byeon Woo-seok recalled their first meeting in the 2016 SBS drama 'Moon Lovers: Scarlet Heart Ryeo.' At that time, Byeon Woo-seok played the role of IU's ex-boyfriend who was unfaithful, and he shared a memory of feeling sorry during a pushing scene. Byeon Woo-seok said, "I wasn't very experienced with acting back then and thought I pushed her lightly, but I remember she fell harder than I expected. Ji-eun was very delicate, and I was tall even then." IU added, "It was originally a falling scene, and I remember that after he pushed me boldly, he immediately helped me up."

IU recalled that they didn't have many scenes together during the past drama filming. He said, "I was happy and felt lovely only when taking prop photos, but then scenes of pushing and crying followed right after." He expressed satisfaction with being able to act for a longer duration in '21st Century Grand Lady.'

They also talked about the casting process for the drama. IU said, "I read the script right away and responded. I read up to episode 4 and was so curious about what would happen next that I wanted to do it." Byeon Woo-seok also said, "I read the script on a plane during an overseas schedule, and as soon as I read it, I thought this is it. It had unexpected elements that drew me in."

They continued to praise each other and shared the atmosphere on set. IU said, "I started filming first, and there were times I felt I was still struggling. When I saw Woo-seok's first shoot, his entrance as Prince Ian was impressive." Byeon Woo-seok said, "When I first filmed with IU, I just thought of her as Seong Hee-joo." Also, IU shared a humorous episode about a 'time difference' in their conversations due to their height difference, which made everyone laugh. She said, "There's a bit of a time lag from when I speak to when it reaches Woo-seok. When I stand and talk, it takes a while for him to respond. We're in such different spaces."