Actor Um Tae-goo / Courtesy of Lotte Entertainment

Actor Um Tae-goo is widely recognized for his deep, husky voice and quiet personality.

Having built a reputation through intense, dark roles, the actor has rarely been associated with high-energy comedy. However, the 42-year-old is set to shock audiences by transforming into a rapper in the upcoming comedy film "Wild Sing."

Um portrays Sang-gu, who constantly talks in a high voice, loves hip-hop and even makes cute faces while dancing.

The actor said Thursday that taking on this unconventional character was a terrifying challenge that pushed him to his physical and mental limits.