Actor Clint Eastwood was approached to play the role of Superman in the 1978 film. However, the actor did not play the role since he wanted to essay Marvel hero Namor the Sub-Mariner. Subsequently, the role was played by Christopher Reeve.

"I was like, 'Superman? Nah, nah, that's not for me.' Not that there's anything wrong with it. It's for somebody, but not me. The Sub-Mariner, that's the one I always liked. I had all of those comics when I was a kid," actor said in an interview with Far Out magazine. 

Son of Atlantis’ princess, Namor the Sub-Mariner made his first appearance in the Marvel Comics in 1939. However, the character appeared in films only in 2022 with Black Panther: Wakanda Forever. It was essayed by Tenoch Huerta.

Eastwood also in a session at CinemaCon in 2015, said, "I read comic books when I was a kid, I don't read them now. I prefer adult-oriented stuff. I mean that in the PG-13 or R sense, but that's as far as it goes."