The industry publication reported Thursday that the role in the serial killer drama will keep Smits in Miami, where he had been starring in the short-lived CBS series "Cane."
While "Cane" focused on the lives of a high-profile Miami family, "Dexter" follows a forensics official who kills serial killers throughout the Florida city.
The Showtime series is set to return for its third season this fall and Smits has signed on to play an assistant district attorney in 10 of the season's 12 scheduled episodes, Variety said.
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