There were rumors of Mamoa being involved with Batman V Superman: Dawn of Justice for months preceding the confirmation, but it’s pretty amazing that he was able to keep the role a secret for so long (even if it meant straight up lying about it). In hindsight, it’s pretty funny how so many people thought he may be playing a villain, the Martian Manhunter, or an anti-hero like Lobo.
In the video below, Mamoa tells Kimmel that he kept his role a secret for “four or five years,” although he confessed with a laugh:
“I told all my friends and family. Of course I did. I told them I wouldn’t say anything, but I’m really bad at secrets.”
He might think he’s bad at keeping secrets, but if Mamoa truly did know he was going to be Aquaman in 2010, then I’d say he did perfectly fine. Late in 2016, Mamoa had this to say about Zack Snyder approaching him for casting:
“Dude, there was a lot of things that went through my head when he said Aquaman. There were a lot of things that went through my mind. I was thinking like, ‘Lobo.’ I’m gonna play some kind of bad guy. I’m like, ‘Who am I gonna play?’ He said Aquaman. I was just like, ‘Come again? Pardon me?’ And then he explained why. I was like, ‘Whoa, buddy. I got your back’.”
Although Mamoa didn’t exactly have as much screen time as some expected in Dawn of Justice, he will have a proper introduction in Justice League on November 17, 2017. Aquaman will also star in his own film along with Amer Heard (Mera), Willem Dafoe (Vulko), and Patrick Wilson (Ocean Master). Directed by James Wan, Mamoa said Aquaman starts production in “four or five months.”
Source: Jimmy Kimmel Live Youtube