When his father goes missing, Smith's character teams up with the Pokémon investigator to find him. Reynolds is used to being a hero.
Starring alongside Reynolds will be Justice Smith, who will be seen in the upcoming Jurassic World: Fallen Kingdom, and Big Little Lies actress Kathryn Newton.
The role is said to be motion capture in nature, sources say.
Considering how Pokémon has sold hundreds of millions of games and billions of trading cards, fans are simultaneously delighted and blown away by the casting choice.
THR is reporting Ryan Reynolds is set to voice Pikachu in Detective Pikachu.
The film will be directed by Rob Letterman, who previously directed the honestly-pretty-good Goosebumps movie.
As of now, Detective Pikachu remains without a release date. Newton is reportedly playing a journalist aiding them along the way.
Ryan Reynolds will play the titular character, Detective Pikachu, who is a pokemon Pikachu that claims to be a great detective.
The movie is based on a 2016 Japanese video game that requires players to solve mysteries with the help of a talking Pikachu dressed like Sherlock Holmes.
He'll play the title character, as The Hollywood reporter first reported. It will also be produced through Universal Pictures, who will distribute the film in the US and most global markets.
Upcoming Huawei P11 to feature 40MP Tri-Camera Setup in the Rear
Newsroom - Travel Smart with Smart Bags - American Airlines Group, Inc
Here are Ireland's most watched YouTube videos of 2017
Pair of super-Earths found orbiting star K2-18
Hunter Pence persuades Giancarlo Stanton to join Giants
Warren Moon Sued For Sexual Assault ... Allegedly Grabbed Asst.'s Crotch
Canada to buy surplus Australian F-18s, says report
Here's where Verizon store net neutrality protests are happening tomorrow
Home Depot announces long-term targets
Mariners, Angels acquire int'l slot money
Lubaina Himid wins Turner Prize for 'uncompromising' approach to race relations
Steam no longer accepting bitcoin due to 'high fees and volatility'
Massive black hole reveals when the first stars blinked on
Willie Taggart leaves OR for FSU, Cristobal named interim head coach
Volkswagen Senior Manager Oliver Schmidt Sentenced To Seven Years
Astronauts have held the first ever pizza party in space!
Pentagon admits U.S. has 2000 troops in Syria