Entitled Partners: Investigator Mamoru Yonezawa's Case File (Aibo Series: Kanshiki Yonezawa Mamoru No Jikenbo), the story will focus on the character of the image and fingerprint expert who played a supporting role in the original movie and TV series.
Seiji Rokkaku will reprise the role, in his first leading appearance. Rokkaku will co-star with Masato Hagiwara (Chameleon). Main Partners stars Yutaka Mizutani and Yasufumi Terawaki will also appear.
Veteran director Yasuharu Hasebe (Stray Cat Rock series) will take the helm. As with the first film's director Seiji Izumi, Hasebe was also a regular director on the six-season hit TV series.
The project, based on a tie-in novel published earlier this year, was greenlit after the success of the first film with hopes the new acting team-up will spawn a spin-off franchise.
As the biggest domestic hit so far this year, Partners has earned $40.8m (Y4.37bn) with an extended run of ten weeks in the top ten since opening at number one on May 3. It's expected to surpass WWII drama Yamato ($47.52m) as Toei's most successful release this decade.
Partners also sold to Hong Kong's Edko Films at this year's Cannes market. The spin-off is slated for release next spring.