"Film Out" was announced by BTS on February 16, 2021, as the ending theme for Signal the Movie Cold Case Investigation Unit (2021).

[1][2] The song was written by BTS member Jungkook in collaboration with the lead vocalist of Japanese rock power trio Back Number, Iyori Shimizu, and the track's producer UTA.

[9] With only three days of availability, the song also topped the Weekly Digital Singles chart for the tracking period dated March 29–April 4 with 32,947 cumulative downloads.

[15] In the United States, with only one day of availability for the tracking week ending April 2, "Film Out" debuted at number 185 on the Billboard Global Excl.

[16] The following week, with its first full period of tracking from April 2–8, "Film Out" debuted on the Billboard Global 200 at number five, with 47.2 million streams and 66,000 sales, becoming BTS' fifth top-10 entry on the chart—the most among all groups since the ranking was launched.

[19] The music video for the song, directed by Yong Seok Choi of Lumpens, was released to Big Hit's YouTube channel at midnight KST on April 2, 2021.