Early concept art for Superman's costume proves David Corenswet was right about the trunks all along

Trunks or no trunks? Superman wearing his underwear on the outside has been fiercely debated ever since the Man of Steel first leapt a building in a single bound.

Concept art for James Gunn's Superman, though, suggests David Corenswet may have been on the money about pushing for his DC hero's iconic red trunks.

As shown off by Graphic/Surface designer Maybelle Pineda on Instagram, an earlier take on Superman's costume features an all-blue design in the torso and legs. See it for yourself below, as well as several intriguing looks at how the suit design came together.

Previously, director and DC boss James Gunn revealed the influence Corenswet had on the final design – and the moment it "clicked" for Gunn.

"We were trying on all these different versions, and we screen tested with trunks and no trunks, and one of the things David said is that Superman wants kids to not be afraid of him," said Gunn in an interview with Gizmodo.

"He's this incredibly powerful – could be considered scary – individual and he wants people to like him. He wants to be a symbol of hope and positivity. So he dresses like a professional wrestler. He dresses in a way that makes people unafraid of him, that shows that hope that shows that positivity. And that really clicked in for me."

Remarkably, the decision to go with the trunks seemingly came down to the very last moment. As costume designer Judianna Makovsky explained to Omelete, the trunks were a "topic of discussion" every day during pre-production, with the trunks ultimately given the thumbs up on the day before filming.

Superman is currently in theaters. Discover what's next with our guides to DCU Chapter One and upcoming DC movies.