Beall is responsible for penning the script for the superhero film from a treatment by director James Wan and Geoff Johns with shooting due to begin in Australia later this year.
The writer - whose previous work includes 2013's 'Gangster Squad' - has revealed that Wan has given him a complete picture of what he wants the movie, starring Jason Momoa as the sea-swelling superhero, and it's going to have a lot of humour whilst also being massive in terms of its "scope".
Speaking to website Collider, he shared: "It's going to be fun, it's going to be really fun. What we've come up with and James especially - he has a really clear idea of the tone he's going to have, and I think 'Aquaman' is one that's going to blow people's minds, not just visually, but I think the story and the scope of it is really great."
Beall is also very excited about the upcoming 'Justice League' film, which will properly introduce Aquaman to the DC Extended Universe alongside Ben Affleck as Batman, Gal Gadot as Wonder Woman, Ezra Miller as The Flash, Ray Fisher as Cyborg and Henry Cavill as Superman.
The creative wordsmith - who wrote a very early draft for 'Justice League', which was eventually rewritten by 'Batman v Superman' writer Chris Terrio - insists it is going to be a much lighter and "poppier" movie than 'Batman v Superman: Dawn of Justice', which needed to be a "sombre" story.
Beall spilled: "I think 'Justice League' again is, what you're going to see - I hope I'm not going to get in trouble for saying this - but it's much more fun, much poppier, than ... I haven't seen 'Wonder Woman' yet, but 'Batman v Superman' was a little more sombre. But 'Justice League' is a lot more fun. And I think that feels to me like the direction those movies are heading now."
'Aquaman' will also star Patrick Wilson as the titular character's evil half-brother Orm Marius - also known as the Ocean Master - Amber Heard as Mera, the Queen of Atlantis, and Willem Dafoe, who will portray a friend and adviser to Aquaman named Vulko.
'Aquaman' will be released by Warner Bros. Pictures on October 5, 2018.