Tuesday, April 18 was an exciting day for James Gunn.

The DC Studios co-head took to Twitter to share a photo of his script for “Superman Legacy”, revealing that pre-production on the highly anticipated film had begun.

READ MORE: James Gunn To Direct ‘Superman: Legacy’ After Saying ‘No’ Years Ago: ‘I’m Incredibly Excited’

“I’m honoured to be a part of the legacy. And what better day than #SupermanAnniversary Day to dive fully into early pre-production on #SupermanLegacy?” he wrote, reminding that day was also the 85th anniversary of the first comic-book appearance of the Man of Steel, in the first issue of Action Comics.

“Costumes, production design, and more now up and running,” Gunn added.

Gunn announced last month that he’d be writing an directing “Superman: Legacy,” a new chapter in the ongoing cinematic history of the iconic superhero.

While there’s been much speculation about who Gunn plans to play the role, he recently revealed he’d been compiling a short list but hasn’t entered into any casting discussions with actors yet.

READ MORE: James Gunn’s Making ‘Private List’ Of Actors Who Could Play The Next Superman

“Haven’t had a single talk with a single actor about the role,” Gunn tweeted. “Just making private lists, prepping material for auditions.”