In the season 3 of the CW's series, Felton, 28, will portray Julian Dorn, a fellow CSI at the Central City Police Department, who suspects there's more to Barry Allen (Grant Gustin) than just his good guy reputation, reported E!Online.
Best known for his role as cunning sorcerer Draco Malfoy in "Harry Potter" movies, Felton has appeared in several TV shows.
He starred in the first season of TNT's "Murder in the First" and miniseries "Labyrinth".
The superhero drama will return with Season 3 on October 4.