Actor Kim Woo Bin let loose while dancing.

In MBC "4 Sons And 1 Daughter" aired yesterday, Kim Woo Bin joined the family as the youngest son.

While digging for horseradish with the mom and other siblings on the show, Kim Min Jong started singing trot for the mom to enjoy and the field soon turned into a dance floor.

Kim Woo Bin seemed shy at first but soon let go of himself as he joined the dancing.

Internet users who saw this commented, "So cute", "He's the cutest youngest son", etc.

Photo Credit: MBC