The Bodyguard actor was rumoured to be taking on the role of Clark Kent's father opposite new Man Of Steel, Henry Cavill.
And now Snyder, who is taking on next year's (12) Superman: Man Of Steel film, has revealed Costner has agreed to the project.
He tells Total Film, "Jonathan Kent is the only father figure Clark has ever had, the man who was there to help Clark understand what he was meant to do in the world as Superman.
"Kevin will be able to communicate the quiet strength of this rural American man who raised the greatest superhero of all time."
Diane Lane will play Superman's mother, Martha Kent, who adopts the young hero when he lands on Earth in a rocket.