From the earliest moments that we knew about Pokemon: Detective Pikachu, Destructoid was at the forefront trying to get Danny DeVito, the only logical choice, to voice the titular role. While ultimately we didn’t get the right actor, we at least have a little validation for our failed quest.
Speaking with Game Informer during a visit to the production studio, the producers of the film made it aware that they had heard the cries of the many who wanted one of the greatest living dark comedy actors to voice a furry little electric rat. So much so that initial animation tests were done for Detective Pikachu using Danny DeVito’s voice.
Source: Destructoid Danny DeVito’s voice was used as a test for Detective Pikachu