A new cast member has been added to the Dexter prequel series, “Dexter: Original Sin”. Patrick Dempsey (Thanksgiving) will star in the upcoming Showtime series.

According to Variety, “He is set to portray Aaron Spencer, the Captain of the Miami Metro Homicide who has a decades-long relationship with Christian Slater’s Harry Morgan.”

Dempsey joins Patrick Gibson (Shadow and Bone), and Molly Brown (Senior Year). Gibson will play the young version of Michael C. Hall’s Dexter Morgan.

James Martinez also stars as Angel Batista, alongside Christina Milian as Maria LaGuerta, Alex Shimizu as Vince Masuka and Reno Wilson as Bobby Watt.

“Dexter: Original Sin” is set in 1991 Miami and revolves around Dexter (Gibson) as he goes from student to avenging serial killer. With guidance from his father, Harry (Slater), Dexter adopts a Code designed to help him find and kill people without being discovered by law enforcement at the same time as he begins a forensics internship at the Miami Metro Police Department.”

“Dexter” showrunner Clyde Phillips will serve as the showrunner on Original Sin.

Executive producers for “Dexter: Original Sin” include Phillips, Michael C. Hall, Scott Reynolds, Mary Leah Sutton, Tony Hernandez, Lilly Burns, Robert Lloyd Lewis, and Michael Lehmann.