Scott Eastwood, 27, who was disowned by his father until he was in his teens, will play tough Chicago officer Jim Barnes who bears an uncanny similarity to renegade cop Dirty Harry, made famous by Eastwood senior in the Seventies.
Studio bosses will introduce Barnes to American viewers on Wednesday in the final episode of the current series of top-rated show Chicago Fire.
A senior NBC executive said: “The episode will also serve as an advance pilot of the spin-off police series whose cast will be led by Scott. It will launch within the year and we believe it will be a ratings success worldwide.”
His role as Jim Barnes in the as yet untitled drama is being viewed as a major breakthrough for the young actor, who is a lookalike for his father and has had a string of minor parts in TV shows and low-budget movies.
He is one of two children fathered by Clint, now 82, and flight attendant Jacelyn Reeves, during their long-running affair in the Eighties while he was living with actress Sondra Locke.
He was only acknowledged by his father in 2002 and his acting potential won him small roles in Clint’s 2006 film Flags Of Our Fathers and 2008 blockbuster Gran Torino.
Scott has never discussed their relationship, saying: “I prefer to focus on the present and future rather than the past.”