Question: Which actress that was a member of South Korean girl group is co-staring in Unexpected Love?
Context: Chrystal Soo Jung (born October 24, 1994), better known by the mononym Krystal, is an American singer and actress based in South Korea.  She debuted in 2009 as a member of South Korean girl group f(x) and has further participated in S.M. Entertainment's project group S.M.  The Ballad.  Aside from group activities, she has also participated in various television dramas such as "" (2011–12), "The Heirs" (2013), "My Lovely Girl" (2014), and "The Bride of Habaek" (2017). Black Pearl (Hangul: 블랙펄) was a South Korean girl group official made up of Oh Nami, Hwl Eun, Young Joo, and Mikka.  When the group debuted in 2007 they marketed as the new girl group to dominate the girl group charts in the following years of 2007 and 2008 alongside some artist Wonder Girls, and Kara.  They were also known to follow the steps of SG Wannabe, SeeYa, and M2M.  In 2009 Mikka left due to personal reasons.  New member Jung Min was added by 2010 or 2011.  As for the 2010 and therefore the group only consisted of the following 4 until their disbandment in 2012. Jewelry (Korean: 쥬얼리 ) was a South Korean girl group formed in 2001 by Star Empire Entertainment.  The group was the longest-running Korean girl group (with more than 2 members) until their disbandment in 2015, surpassing super-group Baby V.O.X. Unexpected Love (also anown as: "Flying Kite" / "Bi Zui!  Ai Ba" / "Biyeon") is an upcoming Chinese-South Korean romantic comedy film directed by Si-Heup Seong and starring Zhang Yixing and Krystal Jung. "Kiss" (Korean: 입맞춤) is a dance single performed by South Korean idol singer Sandara Park, a visual and member of the girl group 2NE1.  The song was used as part of a promotional campaign for Cass Beer.  It features the vocals of her co-member, CL of South Korean girl group 2NE1.  The song was released as her first official single in South Korea and was later included in the album "To Anyone". Kim Chung-ha (born Kim Chan-mi on February 9, 1996), better known by the mononym Chungha, is a South Korean singer.  She is best known for finishing fourth in Mnet's girl group survival show "Produce 101" and as a former member of the now disbanded South Korean girl group I.O.I. D.Holic (Hangul: 디홀릭) was a South Korean girl group formed by Star Road Entertainment (formerly H.Mate Entertainment) in 2014 with five members.  Nine left the group in August 2015, due to personal reasons, and was replaced by new member, Hwajung.  In July 2016, it was revealed through teasers that Danbee and Duri had decided to leave the group, new member, EJ, was added to the line-up.  In February 2017, it was confirmed through a performance that members Hami and Hwajung had departed from the group.  They were temporary replaced with new members, Nayoung and Youjin, although they never officially made their debut.  In July 2017, EJ announced that she would be leaving the group to pursue a modelling career.  The group informally disbanded after the departure of all but one member, with the aim of re-debuting the remaining member, Rena, into a new girl group within a year.  The group has released one mini-album: "Chewy" (2015) and three single albums: "D.Holic Dark With Dignity" (2014), "Murphy & Sally" (2015), and "Color Me Rad" (2016). Kwon So-hyun (born August 30, 1994), is a South Korean singer and actress.  She was known as a member of the South Korean girl group 4Minute, under Cube Entertainment.  She is also a former member of the South Korean girl group, Orange.  Before June 15, 2016 (end of her contract with Cube), Sohyun left 4Minute and the record label along with members Nam Ji-hyun, Heo Ga-yoon, and Jeon Ji-yoon. GP Basic (Korean: 지피 베이직 ) was a South Korean girl group who debuted on August 15, 2010.  At the time of their debut, they were considered to be the "youngest" South Korean girl group with an average age of below 13.5.  The age of their youngest member, Janey, caused controversy followed by the debut of a much younger girl group, G-story, who were all below 10 years old.  This led to new broadcasting regulations in South Korea. Lee Ji-yeon (born February 18, 1984), better known by her stage name Lina is a South Korean singer and musical actress.  She debuted in 2002 as a member of South Korean R&B duo Isak N Jiyeon and disbanded in 2004.  She later re-debut as a member of South Korean girl group The Grace in 2005 and the group currently being inactive.  She currently active as a musical actress.
Answer: Krystal Jung