Moon Hee Jun revealed a story behind his weight increase.

On the January 26th episode of 'Knowing Brothers', Moon Hee Jun appeared as a guest and answered a few questions about his sudden weight change over the last two decades.

The former H.O.T member shared, "I used to have a lean figure as a teenager. I debuted as a 58kg (128 lbs) and stayed active while promoting." Listening to Moon Hee Jun, Super Junior's Heechul concurred, "That's true. Hee Jun hyung used to be really skinny."

Then, Moon Hee Jun revealed, "After the disbandment of H.O.T, I met up with Eun Ji Won (from Sechskies), and we drank alcohol together. Five days of the week, for six straight months.

"Strangely enough, Ji Won's figure stayed the same, while I kept gaining weight. Later in time, Ji Won even apologized to me, thinking that he was the reason for my weight gain," recounted Moon Hee Jun.

During this same episode, the former idol also talked about his past trauma with Kim Jong Kook regarding his body image.