On the January 15 broadcast of MBC’s variety show 'Radio Star,' Goo Hye Sun, Shin Soo Choo, Kwak Si Yang, and Yoon Nam No appeared for the "Clear Skies in Act Two of My Life" special.

During the show, Goo Hye Sun piqued curiosity by sharing that she used a lot of oil-blotting paper before the recording. She explained, "My skin is very acne-prone. My skin produces so much oil that if I don’t use blotting paper, my makeup completely melts off."

Kim Gu Ra then mentioned Goo Hye Sun's hairstyle, where she wore a beanie and had her hair down. He asked, "If you have that much oil, wouldn’t it be better to take off the hat and slick your hair back?" Goo Hye Sun laughed and responded, "There’s a reason I’m wearing a beanie today."

She continued, "I was planning to wash up, but the boiler broke, so I couldn’t wash my hair. The producer asked me to take off my hat, but I really can’t in this situation," she said, making the studio burst out laughing.

Later, Goo Hye Sun shared that she graduated from Sungkyunkwan University after 13 years. She said "I graduated at the top of my class. But at Sungkyunkwan, good grades alone don’t guarantee graduation—you have to complete the Three Achievements System. One of those achievements is filing a patent, and I actually did that."

She explained her invention: "I noticed that students walk around with hair rollers in. I thought, 'Why do hair rollers have to look like that?' So, I created a collapsible hair roller. You won’t find this on the market. I personally think it would be great to include this in airline amenity kits."

Goo Hye Sun also made headlines when she was accepted into KAIST’s graduate program. She addressed rumors, saying, "There were claims that I paid to get admitted. But all KAIST students receive scholarships—it’s a program where they pay us."

When Kim Gu Ra asked, "Since you’ve spent so much time studying and haven’t been as active (in the entertainment industry), how do you support yourself financially?" Goo Hye Sun replied, "I’m funding my studies with the money I saved up when I was younger."

Goo Hye Sun also shared an amusing story about being hit on by college students. She explained, "I think 20-something-year-olds don’t really consider the reality of the situation." She continued to joke, "From their perspective, they think they can date me just because they like me. But I immediately start thinking about what their parents would think."

She concluded by saying, "I don’t have any intention of dating right now. There are things I want to focus on, and I don’t want to be swayed by romance."

SEE ALSO: 'Culinary Class Wars' chef Yoon Nam No shows off friendship with actress Goo Hye Sun