On the episode of "Running Man" which aired on January 19, 2014, actor Lee Jong Suk and actress Song Ji Hyo got involved in the love triangle with Gaeri of Dynamic Duo. On the episode of "Running Man" which aired on January 19, 2014, actresses Park Bo Young and Lee Sae Young, and actor Lee Jong Suk of the recently released film "Boiling Youth" made their appearances.

Park Bo Young, Lee Sae Young, and Lee Jong Suk transformed into high school students and raced across the farms. On this day's episode, Lee Jong Suk and Song Ji Hyo became the secret couple and went on a mission without letting the other Running Man members and guests know. In addition to the holding arms mission, they had to hold hands in front of the other Running Man members and guests without them knowing. While other Running Man members and guests were playing the scarecrow game, Lee Jong Suk and Song Ji Hyo approached each other. When the other Running Man members and guests were busy watching and playing the scarecrow game, Lee Jong Suk and Song Ji Hyo bravely held their hands. Song Ji Hyo then pretended to whisper to Lee Jong Suk.

Gaeri, who was always looking at and looking after his girlfriend Song Ji Hyo, was not aware of the fact that Song Ji Hyo had gotten so close to Lee Jong Suk.