Shazam! is scheduled for release on April 5th, 2019 and, after the massive success of Aquaman, it could be poised to be a major hit. The movie's trailers have been irresistibly fun and the film looks to be cleverly exploring the idea of a child suddenly finding themselves in an adult superhero's body.

Star Zachary Levi looks perfect as the character and, overall, there is a lot of positivity from the fan community towards the film. But, from what we know, how closely does it resemble the source material? What changes have been made to the character for his transition to the big screen and which comics will the movie mostly plunder for material? Read on!

BEFORE 2012, SHAZAM WAS KNOWN AS CAPTAIN MARVEL

Shazam in Captain Marvel 1939 in Fawcett Comics

Shazam was originally created in 1939 by Bill Parker and C.C. Beck for Fawcett Comics. The rights to the character were then bought by DC in 1972 and they integrated him into their universe. The only problem was that they couldn't use his original Fawcett Comics name (Captain Marvel) on the cover, due to legal issues with Marvel Comics, who had their own Captain Marvel.

Thus, DC published the comic under the name 'Shazam!' and over the years this became what most fans knew the character as. It's a funny quirk of history that 2019 will see the big screen debuts of both Marvel and DC's Captain Marvel characters!

HE'S HAD SEVERAL RETCONS OF HIS COMIC BOOK ORIGIN

Over the 40+ years that Shazam has been in publication at DC Comics, he and his associated characters have had more retcons of their origins than most. In the early days, it seemed writers and artists had a very tough time coming up with Shazam stories, even his co-creator C.C. Beck, who said he couldn't bring the new DC stories to life no matter how hard he tried.

In 1987, a reboot entitled Shazam!: The New Beginning was published, which introduced the idea that Billy Batson retains his childish personality when he transforms into the Captain. There was also a 1994 reboot and a 2006 revamp that focused on magic and mysticism.

THE MOVIE IS BASED HEAVILY ON THE NEW 52 RELAUNCH

The upcoming movie is based very heavily upon The New 52 era reboot of Shazam in 2012. The character's entire world was reimagined by writer Geoff Johns (who has also provided modern-day reimaginings of Green Lantern, The Flash and Aquaman which have influenced their big and small screen incarnations) and artist Gary Frank in a Justice League backup feature.

The character was also officially renamed Shazam at this point, which made sense to Johns, who said that it was what most fans knew him as anyway. Frank redesigned the costume to include a long cloak and hood, which the movie costume emulates.

LONGTIME COMICS FANS INITIALLY HATED THE NEW CYNICAL BILLY BATSON

Shazam smiling with lightning coming out of his eyes and chest in DC Comics.

While The New 52 reinvention did a great job of reintroducing Billy Batson, the Wizard, Black Adam, and the Shazam Family into the modern DC Universe, longtime fans were initially resistant to the depiction of Billy as an angry jerk at the outset of the story.

He was a cynical foster child putting on a fake surface display of niceness, but over time his walls dropped and he learned to let people in. He came to appreciate his potential as a hero and the concept of family. It's a more realistic character arc for sure. But, for what it's worth, director David F. Sandberg hinted on Twitter that his Billy Batson 'won't be a huge dickhead'.

THE SHAZAM FAMILY APPEAR IN THE MOVIE BUT USED TO BE VERY DIFFERENT IN THE COMICS

In 1942 writer Otto Binder and artist Marc Swayze created the Marvel Family, a group of superheroes to partner Captain Marvel. There was Mary Marvel, Captain Marvel Jr and Uncle Marvel, amongst others. In The New 52 reboot, they were reimagined as the Shazam Family and were the superpowered alter-ego's of Billy Batson's foster siblings: Mary Bromfield and Freddy Freeman stayed as Marvel Marvel and Captain Marvel Jr.

However, Geoff Johns also added Eugene Choi, Pedro Pena, and Darla Dudley, who also transformed into superheroes upon saying the word 'shazam'. They are all in the movie, so we wouldn't be surprised if they gain their powers in sequels.

DR. SIVANA'S ORIGIN IN THE MOVIE IS DIFFERENT FROM THE COMICS

Mark Strong (who previously played Sinestro in Green Lantern) is playing the villainous Dr Sivana in Shazam!, and his movie origin will reportedly differ from the comics. Traditionally, Sivana was a typical mad scientist with a penchant for developing odd technologies to use against Captain Marvel.

However, in the 2012 reboot, he was depicted as a scientist determined to save his family's life with magic and was inadvertently half-blinded by a magic lightning bolt. In the movie, his backstory is very different: he encountered the Wizard as a child but was rejected and so has spent his life trying to find another way to gain the powers of Shazam.

THE SEVEN DEADLY SINS WILL APPEAR AND SOUND PRETTY COMIC BOOK ACCURATE

In the comics, the Seven Deadly Sins Of Man (pride, envy, greed, sloth, gluttony, wrath and lust) are demons trapped and imprisoned in stone statues by the wizard Shazam. They are kept in his home, the Rock Of Eternity, but would periodically escape to wreak havoc, including during Geoff Johns and Gary Frank's New 52 storyline.

Fittingly, they were recently confirmed to be appearing in the movie by director David F. Sandberg, which will give him a chance to flex the horror muscles he honed on his previous films Lights Out and Annabelle: Creation. It seems likely that the demons will be related in some way to Dr. Sivana's villainous plan.

DC'S NEW SHAZAM TITLE HAS EMBRACED THE LIGHTHEARTED TONE OF THE MOVIE

Shazam! has been marketed brilliantly as a fun, breezy superhero movie. In fact, it has been described as 'Big meets superheroes', which seems accurate given the tone struck in the trailer by Zachary Levi and his young co-star Jack Dylan Grazer. This hasn't always been the tone of the character in the comics, however, although DC's most recent relaunch has clearly made an effort to transfer the 'fun' to the pages.

Geoff Johns has erased much of harder edge that his New 52 story had and has instead embraced some of the zany ridiculousness of the character's Golden Age roots while keeping the story very modern and accessible for people intrigued by the movie.

NEXT: Black Adam Is NOT In Shazam's Post-Credits Scene