On June 7, 2018, JYP Entertainment (JYPE) confirmed that Twice was scheduled to make a comeback in July and that the music video for the lead single was filmed in Japan.[6] Later that month, it was officially announced that Twice would release a special album titled Summer Nights, a reissue of their fifth extended play (EP) What Is Love?. The EP includes nine songs, including the six found on the original release, and three new songs, including the single, "Dance the Night Away", "Chillax" and "Shot Thru the Heart", which was written by Twice's Japanese members Momo, Sana and Mina.[7][8][9][10]
A short video preview of the three new songs was released on July 8.[11] The album, along with the music video of "Dance the Night Away", was officially released the next day on various music portals.[1][12][13][14]
Kim Bo-hyeon – design (A&R), album art direction and design
Kim Tae-eun – design (A&R), album art direction and design, and web design
Choi Jeong-eun – design (A&R) and album art direction and design
Lee So-yeon – design (A&R), album art direction and design, and web design
Seo Yeon-ah – design (A&R) and web design
Choi Hye-jin – recording and mixing engineer, digital editor (on "Dance the Night Away")
Lim Hong-jin – recording and mixing engineer
Eom Se-hee – recording and mixing engineer
No Min-ji – recording engineer
Tony Maserati – mixing engineer
James Krausse – mixing engineer
Lee Tae-seop – mixing engineer
Ko Hyeon-jeong – mixing engineer
Master Key – mixing engineer
Kwon Nam-woo – mastering engineer
Naive Production – video director
Kim Young-jo – video executive producer
Yoo Seung-woo – video executive producer
Kwak Gi-gon at TEO Agency – photographer
Jung Nan-young at Lulu – hair director
Son Eun-hee at Lulu – hair director
Choi Ji-young at Lulu – hair director
Jo Sang-ki at Lulu – makeup director
Zia at Lulu – makeup director
Jeon Dal-lae at Lulu – makeup director
Won Jung-yo at Bit&Boot – makeup director
Choi Su-ji at Bit&Boot – makeup director
Oh Yu-ra – style director
Shin Hyun-kuk – management and marketing director
Kang Da-sol – choreographer
Kim Sun-mi – choreographer
Nana choreographer crew – choreographer
Today Art – printing
Moonshine – all instruments (on "Dance the Night Away")
Wheesung (Realslow) – vocal director (on "Dance the Night Away")
Kwon Seo-young – background vocals (on "Dance the Night Away")
Jung Eun-kyung – digital editor (on "Dance the Night Away")
Lee Woo-min "collapsedone" – all instruments, computer programming, guitar, and synths (on "Chillax" and "What Is Love?"), piano (on "What Is Love?")
Friday of Galactika – vocal director (on "Chillax"), vocal producer and background vocals (on "What Is Love?" and "Stuck"), recording engineer (on "Stuck")
E.Na – background vocals (on "Chillax", "What Is Love?" and "Stuck")
David Anthony Eames – all instruments and computer programming (on "Shot Thru the Heart")
Kevin Oppa – vocal director (on "Shot Thru the Heart")
Park Sung-mi – background vocals (on "Shot Thru the Heart")
Park Soo-min – background vocals (on "What Is Love?", "Sweet Talker" and "Ho!")
Erik Lidbom – all instruments, computer programming, and digital editor (on "Sweet Talker")
Armadillo – vocal director (on "Sweet Talker")
Jiyoung Shin NYC – additional editor (on "Sweet Talker", "Ho!", and "Dejavu")
The Elev3n – all instruments, computer programming, and digital editor (on "Ho!")
Kim Seung-soo – vocal director (on "Ho!")
Mental Audio (Eirik Johansen and Jan Hallvard Larsen) – all instruments and computer programming (on "Dejavu")
^"World Albums". Billboard. Archived from the original on 2018-09-17. Retrieved July 18, 2018.
^"年間 アルバムランキング – 2018年度". Oricon News (in Japanese). Oricon ME Inc. Archived from the original on December 20, 2018. Retrieved December 20, 2018.
^"2018년 Album Chart". Gaon Chart (in Korean). Korea Music Content Industry Association. Archived from the original on January 11, 2019. Retrieved January 11, 2019.
^"올해의 가수 (앨범) 후보자" [Artist of the Year (Album) nominees]. 8th Gaon Chart Music Awards 2018 (in Korean). KMCA. Archived from the original on January 23, 2019. Retrieved January 23, 2019.
^"Summer Nights". iTunes. Apple Inc. Archived from the original on July 10, 2018. Retrieved July 10, 2018.