On the 13th's episode of JTBC's 'Witch Hunt', MC Shin Dong Yup told Sung Si Kyung that his end-of-the-year concerts were now sold out. He replied, "I was really worried about it, so I'm thankful. I'm going to work really hard on the concert."

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Shin Dong Yup asked, "When you're getting ready for a concert, don't you drink less?", and Sung Si Kyung answered, "I'm currently not smoking. It's been 1 week. It's the first time in my life that I'm attempting not to smoke."

He was then asked the benefits of not smoking, to which he answered, "I don't know yet. But I hate people who smell like cigarettes."