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During a recent filming of MBC's 'Quiz to Change the World', when asked what Hyeri calls him, Tony commented, "At first, [Hyeri] called me 'daesunbaenim' (referring to a sunbae who is much older or has much more experience), but now she just calls me 'oppa'... The best part about our relationship is that we understand each other well."

He also surprised fellow guests and MCs on set when he mentioned that because of their 16-year age difference, the two had previously tried to stop seeing each other during the early stage of their relationship. Concerned about the age gap, Tony revealed that he had suggested that they break up. In attempts to keep her off his mind, he even deleted her phone number off his phone, but apparently, because of something that Hyeri did later, they decided to get back together.

To find out what Hyeri did to save their relationship, we'll all have to tune in for the episode of 'Quiz to Change the World' airing on the 26th at 11:15 PM KST!