'Superman' director James Gunn has revealed Krypto the Dog will be in the movie and added the character "changed the shape of the story".

The DC blockbuster is set to introduce the hero's super-powered mutt in what will be Krypto's cinematic debut and the 58-year-old filmmaker has now revealed the idea of including the dog in the flick came to him after he adopted his rescue pup Ozu in 2022.

On X, Gunn shared a still of Superman (as played by David Corenswet) and Krypto and captioned the post: "Krypto was inspired by our dog Ozu, who we adopted shortly after I started writing 'Superman'.

"Ozu, who came from a hoarding situation in a backyard with 60 other dogs and never knew human beings, was problematic to say the least.

"He immediately came in and destroyed our home, our shoes, our furniture – he even ate my laptop. It took a long time before he would even let us touch him.

"I remember thinking, ‘Gosh, how difficult would life be if Ozu had superpowers?’ – and thus Krypto came into the script and changed the shape of the story as Ozu was changing my life.

"What better time to debut the not-so-good-good-boy Krypto than #AdoptAShelterDog month. Btw, Ozu today, is, fairly often, a very good boy."

The film – which is due to be released in July 2025 - will follow Superman as he attempts to balance his Kryptonian heritage and his human upbringing, all while Lex Luthor (Nicholas Hoult) plans to take the hero down.

Previously, Corenswet revealed he could no longer fit into his pants after bulking up for the picture, which also stars Rachel Brosnahan, Milly Alcock, Nathan Fillion and Isabela Merced.

During an appearance on the 'Manly Things (Sort Of)' podcast, the 31-year-old actor explained: "I wasn’t 238 [pounds] when we started shooting. I was 238 at my max.

"It was so awesome, I wanna go back. I put on like one of those crew neck sweatshirts … Champion. And I put on one of those sweatshirts - like an XL or double XL - and I was like, ‘I fill this out. This is amazing'. I didn’t fit into any of my pants."