9 details you probably didn't know about the making of 'Aquaman'

Warner Bros.Jason Momoa and Amber Heard are great in ‘Aquaman.’

Warning: There are some spoilers ahead if you have not seen “Aquaman.”

Aquaman” is finally in theatres and is heading for a big opening weekend at the box office.

While Jason Momoa is the perfect Aquaman, did you know he originally tried out to play another hero in the DC superhero universe? The actor wound up playing Aquaman instead and had to keep the secret of playing the King of the Seven Seas for years.

INSIDER went through “The Art and Making of ‘Aquaman,'” which features interviews with the cast, director, and production team behind the movie along with gorgeous artwork and behind-the-scenes photos and concept art that went into making the film.

The book, from Insight Editions will be out January 1, 2019. Until then, keep reading to see a few things you may not know about “Aquaman.”

Jason Momoa kept the secret about playing Aquaman for years.

Courtesy Insight EditionsMomoa lied to people who thought he may be playing Aquaman.

“When I first got the role, I couldn’t tell my friends or even family members,” Momoa says in the book. “[I] had to straight up lie to everyone who asked me about it directly. I was hired years before the movie started production, even before James Wan came on as director. Hell, I was in the role before there was even a script. I was the first person officially involved with the film.”

“I hated doing interviews,” he added. “Everyone would be like, ‘You’re playing Aquaman!’ And I would have to lie and say, ‘Nope, not happening. I don’t know what you’re talking about.’ I had to lie nonstop.”

Momoa told Jimmy Kimmel he kept the secret for four or five years.

Momoa originally auditioned to play Batman before he was cast as Aquaman.

Warner Bros.Could you have seen him as the Dark Knight?

“Man of Steel” director, Zack Snyder, had Momoa come in to test to play Batman.

“I think when I did the audition for ‘Batman,’ I didn’t play it like I was supposed to,” said Momoa. “I just played it completely different and I think that’s what Zack liked.”

Instead, Snyder offered Momoa the opportunity to play Aquaman as long as he kept it a secret.

Nicole Kidman’s likeness was used in concept art before she even agreed to be in the movie.

Warner Bros.The drawings weren’t necessary. Kidman wanted to work with director James Wan.

According to the art book, the filmmakers were so into the idea of casting Kidman as Aquaman’s mum that the actress’ likeness was used in concept art and wardrobe drawings for the character of Atlanna.

Arthur Curry’s home is in Maine, but the actual sets were created in Australia.

Warner Bros.It only looks like Maine.

All of “Aquaman” was shot in Australia. Everything that resembles Amnesty Bay, Maine, was actually recreated near Main Beach on the Gold Coast of the continent.

Director James Wan really wanted characters to have capes, something which didn’t make logistical sense to the production design team. A compromise was made.

Warner Bros.You can see a few characters wearing capes during the Ring of Fire sequence.

“James was keen on having characters like King Orm using capes. I asked, ‘Well, can we forgo the capes?’ Because a cape under the water won’t do anything except create drag,” said costume designer Kym Barrett. “Then we thought, ‘What if they only wear capes for ceremonial purposes?’ Like how a member of a royal family might wear a cape to a coronation, or the royal guardsmen.”

The scariest moment in the movie reportedly convinced Warner Bros. to make “Aquaman.”

Warner Bros.This scene feels straight out of a James Wan horror movie, but it works.

There’s a scene late in the movie where Aquaman and Mera are getting attacked by the Trench, a group of evil fish-people, on a fishing boat and dive into the ocean with a flare in one of the movie’s most beautiful moments.

“We created an animatic version of that scene that we showed the studio, and it hearkened back to James [Wan’s] pure horror days,” said producer Peter Safran. “It’s like the ‘Creature from the Black Lagoon,’ but the 2018 version. It’s pure horror, it’s fantastic, and I think it’s one of the things that really got the green light for the movie.”

Willem Dafoe wanted his character, Vulko, to be like an Obi-Wan Kenobi type, apparently.

Warner Bros.Vulko does feel a bit like a Jedi master teaching an apprentice in ‘Aquaman.’

“Here is this really highly regarded thespian and he’s talking to me about doing this crazy action stuff. He told me that’s why he signed up to do this role in the first place,” said “Aquaman” producer Peter Safran. “He did not want to just be relegated to the sideline as the older, wiser guy. He wanted to get in there. He wanted to be like Obi-Wan Kenobi, this old samurai guy.”

Yahya Abdul-Mateen II was reportedly the only person seriously considered to play Black Manta.

Warner BrosBlack Manta in ‘Aquaman.’

“We just met with him and we’re like, this is the guy. It was really important for Manta to be a guy that both has a humour to him but also a true intensity so that he can be a scary, scary adversary,” said Safran.

The production team actually built the throne room that Mera and King Orm are seen in with Aquaman.

Warner Bros.Patrick Wilson on set of ‘Aquaman.’ He plays Aquaman’s brother, Orm, who is trying to destroy the world.

You might think it’s a giant CG room when you see the movie, but the main throne is actually real.

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