Kang Ji-hyun, known professionally as Soyou, is a South Korean singer. She is best known as a former member of the South Korean girl group Sistar.

Kim Hyung-soo, better known by his stage name K.Will (Korean: 케이윌), is a South Korean singer. The name is a combination of the first letter 'K' of his last name 'Kim' and the English word 'Will', which means will. He debuted in 2007 and has since become known for his chart-topping ballads. He has also been dubbed the "Prince of OST" for his frequent Korean drama soundtrack appearances.