Armie Hammer said his Batman would have been "severely psychologically, almost deranged".
The 31-year-old actor's name was attached to star as the Caped Crusader in the 'Justice League' film directed by filmmaker George Miller, which almost became a reality back in 2009, and Hammer revealed he had already begun dissecting the iconic character.
Speaking on the Happy Sad Podcast, Hammer said: "It was pre-Christian Bale but the Christian Bale Batman had a lot more in common with it than any of the previous ones, whether it be George Clooney or Michael Keaton, which were almost campy.
"This was one about a guy who is severely psychologically, almost deranged. It was dark and it was really intense and this guy had major trust issues, the whole thing. It was a great concept and a really cool idea."
At the end, Hammer was more or less unknown compared to the last few actors to have taken the mantle of Bruce Wayne and he admitted it was "crazy".
He said: "That was crazy. That was nuts. I was just a kid with a goofy name."
Although the project - which was titled 'Justice League Mortal' - was abandoned, Hammer recalled how the entire project was shrouded in secrecy, even during the audition stage.
He said: "I can specifically remember getting the phone call, and them being like 'you go the part in the movie'. We didn't know what part we were going in for. They didn't say you were going in for Batman. It was nothing.
"Literally nothing. They didn't even give you scenes from the movie. My audition scene was the Ned Beatty monologue from 'Network'."
Most recently, the role of the world's greatest detective has been given to Ben Affleck who first starred as the iconic DC Comics character in 'Batman v Superman: Dawn of Justice'.
He is now reprising his role in 'Justice League' alongside Henry Cavill (Superman), Gal Gadot (Wonder Woman), Jason Momoa (Aquaman), Ezra Miller (The Flash) and Ray Fisher (Cyborg).