The B-side is "Daisuki Datta" (大好きだった), theme song to the 2018 anime Yo-kai Watch: Forever Friends.

Tohoshinki premiered a performance of the song at the Saitama Super Arena, the first leg of their Tomorrow Tour on September 26, 2018.

Tohoshinki performed "Jealous" for the first time in September 2018, on the opening day of their Tomorrow Tour in the Saitama Super Arena.

[3] Aside from a standard CD single and an exclusive fanclub edition, the third version included a 24-page booklet that was only made available in first press limited releases.

Japanese morning publications were the first to break the news that the single's B-side "Daisuki Datta" (大好きだった) would be the theme song to the 2018 anime film Yo-kai Watch: Forever Friends.

[4] According to the film's director Shigeru Takahashi, Tohoshinki was chosen for the theme song because of their wide appeal across generations.

[10] Tohoshinki performed "Jealous" at their nationwide Tomorrow Tour, which lasted from September 2018 to January 2019.

On August 18, 2019, Tohoshinki performed "Jealous" at the a-nation Music Festival, which they headlined at the Yanmar Stadium Nagai in Osaka.