SISTAR made a guest appearance on the August 19th episode of Yoo Hee Yeol's 'Sketchbook' and MC Yoo Hee Yeol truly felt the generation gap after discovering he was only a year younger than Hyorin's mother. "My mother is a huge fan of yours," Dasom stated. "We would always watch your show after dinner together." To which Yoo Hee Yeol jokingly responded, "Your mother? I usually attract much younger ladies." But the members insisted on informing him that he was actually around the same age of Hyorin's mother. It was revealed that Hyorin's mother was born in 1970, and Yoo Hee Yeol was only a year younger. Although he was shocked, Yoo Hee Yeol laughed it off and remarked, "She's a year-older noona!" Additionally, the girls put on a wonderful performance by covering MARY MARY's "The Real Party," check out the hot performance below! Source: Newsen via Nate