Stranger (stylized in all capitals) is an extended play (EP) marketed as the fourth single of Japanese boy group JO1.

It features the participation of various Japanese lyricists and South Korean producers such as Yhanael [ja], Jung Ho-hyun, Score, Megatone, KZ, Full8loom and others.

[4][5] At the end of the performance, leader Sho Yonashiro announced the group would release their fourth EP single Stranger on August 18.

[8] Stranger consists of a total of six songs that were released into three different physical editions with "Real" served as the lead track.

[6] The special track of the limited edition A and B, "Freedom" and "Dreaming Night", were released as a digital single on July 7 and June 25, respectively,[9][10] while "Icarus" was pre-released on August 11 alongside its performance video.

[11] The limited edition A comes with a DVD bundle consisting of a variety segment with the members called Beautiful Stranger.

[1][2] Jung Ho-hyun (e.one), who was in charge of lyrics, composing, and arrangement, has worked with groups such as Wanna One and Exo.

[13] It was used as the theme song for the 18th edition of Fuji TV's annual summer event The Odaiba held on August 14–September 5, 2021,[15] and later peaked at number one on the Billboard Japan Hot 100.

[19][20] The promotion for Stranger started with the first performance of B-side track "Dreaming Night", which had been used as the opening song of MBS's drama Love Phantom [ja], at the KCON:TACT 4U on June 25, 2021.

[22] JO1 then performed another B-side track "Freedom" on July 7 at the launching of Yves Saint Laurent Beauté's fragrance web commercial video which featured the song,[10] and released a special performance video on the group's official YouTube channel on the same day.

[32][33] On September 23, JO1 participated in a joint live concert along with other post-Produce 101 Japan groups, OWV and Enjin, titled KCON World Premiere: The Triangle.