In 2009, Kyuhyun sang the remake of Yoo Young-suk's "7 Years of Love" (7년간의 사랑) for Yoo's 20th-anniversary tribute album. Kyuhyun first performed the song on the television program "Yoo Hee Yeol's Sketch Book". On June 30, the song was released as a digital single as well as on Yoo's tribute album, with all proceeds donated to UNICEF. Following the success of his solo track, Kyuhyun alongside bandmate Donghae and actress Han Ji-min appeared in the music video "Happy Bubble," a commercial theme song for facial wash product Happy Bath on August 20.