On a recent airing of JTBC's 'I'm Going to School,' Nam Joo Hyuk raised the suspicion of Kangnam going under the knife after seeing Kangnam's past school photos.�

On this day, Nam Joo Hyuk and Kangnam were seen visiting Kangnam's high school in Hawaii and, with the help from the school's principal, they were able to retrieve Kangnam's past yearbook photos. Surprised by the pictures, Nam Joo Hyuk playfully commented, "Where did you get work done?"�

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Then Kangnam explained that he was around 90 kg (~190 lb) at the time the photos were taken and that he had to lose weight before debuting in�M.I.B.�

However, Nam Joo Hyuk refused to let go of the topic and continued to tease Kangnam, saying, "Something about your face changed, but I don't think it was because you lost weight. You definitely had something done. You're definitely caught this time."�

Meanwhile, as it was previously reported, Kangnam and Nam Joo Hyuk will be joined by EXID's Hani and AOA's�Jimin in the upcoming episode of 'I'm Going To School'!