CNBLUE is a South Korean pop-rock idol band.
 The quartet made its debut in Japan under AI Entertainment in 2009, where it released its first two independent mini-albums "Now or Never" and "Voice".
 Written entirely in English, the former contained two songs by frontman Jung Yong-hwa ("Just Please" and "Love Revolution"), while the latter contained one ("Y, Why...").
 The band proceeded to debut in its home country under FNC Entertainment with the mini-album "Bluetory" (2010), in which Jung contributed to the Korean lyrics of two tracks alongside the record label's CEO Han Seong-ho: "Love Revolution" and "Y, Why...".
 With CNBLUE's followup "Bluelove", in addition to the songs penned solely by Jung ("Tattoo" and "Love Light"), drummer Kang Min-hyuk co-wrote "Sweet Holiday" with Han.
Jung Yong-hwa (; ] ; born June 22, 1989) is a South Korean musician, singer-songwriter, record producer and actor.
 He is the leader, lead vocalist and rhythm guitarist of the rock band CNBLUE.
 Jung made his television debut in "You're Beautiful" (2009), and has since starred in television dramas "Heartstrings" (2011), "Marry Him If You Dare" (2013) and "The Three Musketeers" (2014).
 In 2015, Jung made his solo debut with the album "One Fine Day".
One Fine Day (어느 멋진 날 ; Eoneu Meotjin Nal) is the debut solo studio album by South Korean vocalist and CNBLUE member Jung Yong-hwa.
 It was released on January 20, 2015, under FNC Entertainment and distributed by CJ E&M.
 As CNBLUE's promotions for their mini-album "Can't Stop" (2014) came to a close, the label announced plans for Jung to release a solo album within the year.
 Since the album's inception, he sought to distance himself from the band's sound and include various musical styles on the record.
 Ultimately, he conceived a collaborative album with an array of musicians.
Heartstrings (; lit.
 You've Fallen for Me) is a 2011 South Korean television series starring Park Shin-hye and Jung Yong-hwa.
 It aired on MBC from June 29 to August 19, 2011 on Wednesdays and Thursdays at 21:55 for 15 episodes.
"Mileage" (마일리지 ; "Mailliji " ) is a song by South Korean musicians Jung Yong-hwa of CNBLUE and Yang Dong-geun (YDG).
 Released on January 9, 2015, it serves as the pre-release single of the former's debut solo studio album "One Fine Day" (2015).
 While filming for the television series "The Three Musketeers" (2014), Jung was inspired by YDG's affection towards him family on set to compose the song.
 Upon release of Jung's album, the two performed "Mileage" on music programs and talk shows.
 The song debuted and peaked at number 57 on South Korea's national Gaon Digital Chart, selling over 78,000 digital downloads since its release.
Jessica Jung (born April 18, 1989), known professionally as Jessica, is an American singer, songwriter, actress, model, fashion designer, and businesswoman currently based in South Korea.
 Jung was born and raised in San Francisco, California.
 At the age of eleven, she was discovered by South Korean entertainment agency S.M. Entertainment and subsequently moved to South Korea.
 In 2007, Jung debuted as a member of the South Korean girl group Girls' Generation.
 The group later became one of the best-selling artists in South Korea, and one of South Korea's most popular girl groups nationwide and worldwide.
"You, My Star" (별, 그대 ; "Byeol, Geudae " ) is a song by South Korean musician Jung Yong-hwa of CNBLUE.
 Written in dedication to his fans, the song was released in December 23, 2013, under FNC Entertainment.
 Two days prior, Jung performed the song on the year-end music program "SBS Gayo Daejeon".
 "You, My Star" debuted and peaked at number 22 no South Korea's national Gaon Digital Chart; all proceeds went to the label's charity Love FNC.
This is a list of awards and nominations received by South Korean rock pop band CNBLUE.
 The band debuted in 2009 in Japan and 2010 in South Korea with four members: Jung Yong-hwa, Lee Jong-hyun, Kang Min-hyuk and Lee Jung-shin, under FNC Entertainment.
The Package () is an upcoming South Korean television drama starring Jung Yong-hwa, Lee Yeon-hee, Yoon Park and Choi Woo-shik.
 It will be aired in both South Korea and China.
 In South Korea, it will be aired on JTBC every Friday and Saturday at 20:30 (KST) on October 13, 2017.
Park Shin-hye (, born 18 February 1990) is a South Korean actress and singer.
 She gained recognition for starring in melodramas "Stairway to Heaven" (2003) and "Tree of Heaven" (2006).
 Considered one of the most prolific actresses of her age, Park received further recognition for her roles in the television dramas "You're Beautiful" (2009), "The Heirs" (2013), "Pinocchio" (2014–2015) and "Doctor Crush" (2016).

Question:  What is the other profession of Jung Yong-hwa's costar, who is considered the one of most prolific actresses of her age in South Korea?
Answer: singer