Ken Watanabe is joining Ryan Reynolds in the first-ever-live-action Pokémon film, 'Detective Pikachu'.

The 58-year-old actor has signed up to play Detective Yoshida, a role specifically created for the movie, which is based on the popular gaming franchise, according to The Hollywood Reporter.

The film is set to follow Justice Smith's teenage character Tim Goodman, who has to team up with the mouse-like Pikachu in order to find his father who has been kidnapped.

Kathryn Newton is set to star as a journalist.

In the game franchise, Detective Pikachu isn't as agile as the normal Pikachu, so has to rely on his intelligence to beat his enemies, and he gets help from Tim who is the only boy who can understand what the he says, to solve Pokémon-related crimes.

Rob Letterman is set to helm the new movie and has teamed up with Legendary Entertainment to oversee the upcoming movie which has been written by 'Guardians of the Galaxy's Nicole Perlman and Alex Hirsch who has worked on 'Gravity Falls', according to Variety.

Rather than a standalone film it is expected that 'Detective Pikachu' will act as a launch pad for a franchise.

The Pokémon Company's long-standing movie collaborator, Toho, will handle distribution of the film franchise in Japan, as it recently worked in partnership with Legendary on the reboot for the 'Godzilla' franchise.

Ken was nominated for an Academy Award for Best Supporting Actor for 'The Last Samurai' and has starred in Christopher Nolan's 'Batman Begins' and 'Inception', along with movies including 'Godzilla' and 'Letters From Iwo Jima'.