Jung Ji-hoon, better known by his stage name Rain or Bi Rain, is a South Korean singer, songwriter, dancer, actor, and record producer. Rain's musical career includes seven albums, 28 singles and numerous concert tours around the world. He achieved breakthrough success with his third Korean album, It's Raining (2004), which spawned the number one single of the same name. The album sold over 200,000 copies in South Korea and one million copies throughout Asia, and established Rain as an international star.

Sang-doo! Let's Go to School! is a 2003 South Korean television series starring Rain, Gong Hyo-jin, Lee Dong-gun, Hong Soo-hyun and Song Min-joo. It aired on KBS2 from September 15 to November 4, 2003 Mondays and Tuesdays at 21:50 for 16 episodes.