Secret 시크릿 is a girl group formed by TS Entertainment in 2009. The group originally debuted with four members: Jun Hyosung, Jung Hana, Song Jieun, and Han Sunhwa. Sunhwa officially departed from the group in October 2016. They released their debut single "I Want You Back" in October of 2009.
The documentary Secret Story which aired on Mnet introduced Secret to the public. The show chronicled the members' debut process and aired their invitation-only debut showcase which took place on September 29, 2009. On October 13, 2009, Secret officially debuted with the release of the music video of "I Want You Back," their first single. Two days later, on October 15, 2009, they had their first live stage on "M Countdown." Secret participated in the "Master of Study" OST with the song "Friends," which was released in January 2010.
On March 31, 2010, Secret revealed the music video for "Magic," the main track of their debut mini album Secret Time. Secret had their comeback performance for "Magic" on "M Countdown" on April 8, 2010. The song peaked at 5 on the Music Bank K-Chart.
Secret released their second mini album, Madonna, on August 12, 2010. The music video for the title track was released on August 11, 2010. Kang Jiwon and Kim Kibum, the composers who wrote "Madonna," highlighted that the inspiration behind the song is about living with confidence by becoming an icon in this generation, like the American singer Madonna. "Madonna" was better received than "Magic," topping every major online music chart within two weeks and peaking at 1 on the Gaon Chart. The song also won the Main Award at the 20th Seoul Music Awards. On December 9, 2010, Secret attended the 25th Golden Disk Awards and won the Newcomer Award.
Secret released the single "Shy Boy" in January 2011. On January 13, Secret won their very first music show award on "M Countdown." Secret stayed at number one on "Music Bank" for three consecutive weeks. During that time, Secret also won a mutizen award on "Inkigayo." They released their second single album, Starlight Moonlight, on June 1, 2011. The song won Secret their second mutizen on "Inkigayo" with the song.
On August 3, 2011, the group released their first single in Japan, "Madonna," which debuted at number nine on the Oricon charts.
On October 18, 2011, Secret released their first studio album, Moving in Secret. On November 16, 2011, Secret released their first Japanese mini album, Shy Boy. They attended the KBEE (Korea Brand & Entertainment Expo) in Paris, France, from December 1 to 3, 2011.
In February 2012, Secret released their 2nd Japanese single, "So Much For Goodbye." On February 22, they won two Singers of the Year awards at the Gaon Chart Awards for "Shy Boy" and "Starlight Moonlight." In March, the group held their first head-lining tour in Japan named Secret 1st Japan Tour. It took place in Osaka on March 5, Nagoya on March 7, and Tokyo on March 8. Secret released their 3rd Japanese single, "Twinkle Twinkle," on June 13. "Twinkle Twinkle" was used as the ending theme song of the "Naruto" spin-off, "Naruto SD: Rock Lee and his Ninja Pals." The group released their first studio album in Japan named Welcome to Secret Time on August 22. The Japanese version of "Love Is Move" served as the lead single. The album also included their Korean tracks “Madonna” and “Shy Boy,“ the Japanese versions of “Love Is Move” and “Starlight Moonlight,“ and two original Japanese singles, “So Much for Goodbye” and “Twinkle Twinkle.“
In September, Secret released the single "Poison" in South Korea. The song was an upbeat dance track written and produced by Kang Jiwon and Kim Kibum whom they worked with on their previous hit singles. According to TS Entertainment, “Poison" had "unique characteristics and colors of Secret but will have a change in concept from the cute and friendly image to a sexy and feminine concept.”
The single "Talk That" was released on December 4. It was produced by Shinsadong Tiger, who had previously worked on their hit track "Magic," The music video for "Talk That" was directed by Zanybros' Hong Wonki. "Talk That" received generally positive reviews from critics, most of whom had praised the song for its mature musical style and concept as opposed to their previous singles.
On the night of December 11, 2012, Secret was involved in a car accident. Hyosung, Jieun, and Sunhwa received only a few scratches and knee pain, but Hana suffered broken ribs and a bruised lung. On December 27, Han Sunhwa and B.A.P's Yoo Youngjae teamed up to released a digital single entitled "Everything is Pretty" as a present for Secret and B.A.P fans.
In January 2013, Secret continued to perform "Talk That" on various music and award shows without Hana. Hana ended her hiatus and officially rejoined Secret when she performed at the 22nd Seoul Music Awards and they won a bonsang award. On March 29, Secret held their solo concert in Singapore, performing in front of 5,000 fans at the Marina Bay Sands Convention Hall. Subsequently, Secret's fourth mini-album, Letter from Secret, with the song "YooHoo," was released on April 30. In June, Secret signed with Kiss Entertainment for future Japanese activities. They also moved from Sony Music to Universal Music Group Japan (Universal D Sub-Label). On December 9, the group's third single album, Gift From Secret, featuring the song "I Do I Do" as its lead single, was released.
In mid-January 2014, Secret released the Japanese version of their Korean single "I Do I Do" along with a music video, marking their first Japanese release with Kiss Entertainment. On May 29, Tower Records Japan revealed that Secret would release a single album in Japan on July 23, 2014. In August, Secret released their fifth mini album, Secret Summer, with the song "I'm in Love" as its lead single.
On September 26, 2016, it was announced that Sunhwa would be leaving the group after deciding not to renew her contract with TS Entertainment in order to pursue a career in acting. Sunhwa's contract with TS Entertainment was terminated on October 13th. The group continued with the remaining three members.
On January 28, 2017, TS Entertainment confirmed that Secret will return as a trio in the second half of 2017.