Kightley - who shot to fame in Sione's Wedding - is equally amped at the prospect.
"Having Sam Neill in it lifts that excitement to another stratosphere. He is the man.
"It is awesome that he is going to be on our TV screens again, and a massive honour for us that he's chosen this project to do that." Kightley says: "Now we have to do justice to his involvement and make sure it is good."
Producer Steven O'Meagher says the draft scripts for Harry attracted the interest of Neill and negotiations took place over a month while the actor worked on productions in the United Kingdom and the United States.
"Sam Neill is one of our greatest actors and his agreeing to play Stockton is a huge endorsement on the quality of the series," O'Meagher says.
"Sam and Oscar have a personal friendship which will translate into great on-screen chemistry.
"Stocks is a mentor, a boss and a mate to Harry, and is one of the two most important people in Harry's life. Their scenes together will crackle. Viewers are in for a treat."
TV3 head of comedy and drama Rachel Jean says Harry was shaping up to be an outstanding series, raw, emotional and compelling.
Harry is being produced by Desert Road for TV3.