R&B singer Zion.T revealed his disappointed heart at singer IU on MBC's Radio Star on this week's airing of the show.

Zion.T talked about his friendship with the Nation's Little Sister and her work ethic.

When the Radio Star hosts asked about his observations towards IU on "Infinite Challenge" and how she seems very focused on work, the "Yanghwa BRDG" singer confirmed and agreed.

"She seems pretty crazy about work," Zion.T responded.

However, that wasn't the only concern.

As both singers knew eachother prior to the popular variety show, Zion.T was jokingly saddened by IU's taste in music.

"IU said she likes Hyukoh's songs," he explained. "She said she likes my songs too but she didn't talk about that on the show."

Zion.T's small comment on IU's music taste created laughs in the Radio Star studio.