The title refers to actor Clint Eastwood who was starring in the TV Western Rawhide (1959) long before he performed in his Italian Westerns and his Dirty Harry role.
Clint said, at the time, this was his most challenging role, navigating how to play himself.
This was not actually Clint Eastwood's first onscreen interaction with a talking hoofed mammal, which had occurred in one of his earliest movie roles seven years earlier opposite the famous talking mule in Francis in the Navy (1955).