Lee Kwang Soo was sent into a panic on the latest episode of 'Running Man' when his close friend and guest Wang Ji Hye threatened to blow the whistle on his past dating life!

One of the mini-games featured a game of 'Dangyeonhaji', where two opposing sides would throw questions at each other. The first side that couldn't answer the question with "Dangyeonhaji" ("Of course!") would be the loser.

The questions started, predictably, about their love lives. Although Lee Kwang Soo came out swinging, Wang Ji Hye had a follow-up question that sent him into a tizzy: "There was someone you did a drama with that started off as "oppa" but then progressed into "honey", right?"

Lee Kwang Soo was shocked at her accusation and went into a panic! "There aren't that many people who've played my younger sister!" he yelled.

The list is indeed quite short - who do you think she is?

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