SEE ALSO: 'Superman is Back's Dae Han, Min Guk, and Man Se's calendars in hot demand

During the recording for the upcoming episode of KBS 2TV's 'Superman is Back', Song Il Kook and the triplets continued their vacation in Japan at a hot-spring resort. The triplets entered the water without anything on and cutely babbled regarding the temperature of the water by saying, "Cold~ Cold~" and "Hot~ Hot~".

As the triplets started to loosen up in the hot water, Song Il Kook told them, "Kids, let's move away from using diapers in the new year and open up a new world for your dad," sharing his new year's wish. He then asked Man Se, "Man Se yah, do you think you can stop using diapers now?", but Man Se shook his head in rejection, bringing Song Il Kook to laughter.

Stay tuned for this week's episode of 'Superman is Back', which will air earlier on Sunday at 4:10 PM KST due to a soccer broadcast.