On Instagram, Gunn shared this photo that sees him, Corenswet, and Brosnahan reading Superman comics. “On this day in 1938 the first superhero entered our atmosphere via the imaginations of Jerry Siegel and Joe Shuster,” Gunn’s caption reads. “He gave us someone to believe in, not because of his great physical power, but because of his character and determination to do right no matter what. Happy #Superman Day to all of you! #UpUpandAway.”
