Darth Vader Played a Crucial Role in Helping Christopher Reeve Become Superman – The Hollywood Reporter

Calling the actor a "skinny little kid" when they met for his audition, Richard Donner made Reeve promise he would be able to bulk up for the role.

Darth Vader Played a Crucial Role in Helping Christopher Reeve Become Superman – The Hollywood Reporter

Christopher Reeve: Remembering the 'Superman' Actor's Career

Superman and Christopher Reeve: The Day We Believed Man Could Fly

Darth Vader Actor David Prowse Tried To Land The Lead Role in Richard Donner's SUPERMAN — GeekTyrant

The Man Behind The Mask. From Strongman to Silver Screen Icon…, by Chris Frederick, Nov, 2023

The Silver Screen: Making Superman the Movie

Superman: An Irritated Christopher Reeve Once Accused Brando of “Phoning In” Film Performance – The Hollywood Reporter

How 'Superman' gave rise to superhero movies 40 years ago - The Washington Post

DC History Club: Superman The Movie (May 2020) Quiz, Polls & Discussion - Fan Club Discussions - DC Community