유재석
In 2015, Park released the song "Who's Your Mama?" featuring Lucky J's Jessi. The song became a hit, displacing fellow label-mates Miss A from first spot on the Korean charts. Later that year, he participated in the "Infinite Challenge Yeongdong Expressway Music Festival", forming the duo Dancing Genome with comedian Yoo Jae-suk and releasing the song "I'm So Sexy."