Conan The Barbarian writer/director John Milius will oversee the project.
Rourke tells the Orlando Sentinel newspaper, "John wrote (the) piece from the son and grandson’s point of view, how they saw this mythic figure from their family.
"You see him (Khan) in flashbacks, back when he was in his mid-40s. And back then, being in your mid-40s was being really old."
Genghis Khan was the emperor of the vast Mongol Empire in the 13th century. He united the nomadic tribes of northeast Asia.
He died in 1227 and was buried in an unmarked grave somewhere in Mongolia.