Marvel and DC have always been the two biggest and definitive brands in comic book history and, naturally, that success has transitioned to the big screen. Both brands have produced some ideal comic book adaptations, but Marvel has done so in a much more profound manner. In 2008, Marvel Studios made a rather ambitious move by crafting its Marvel Cinematic Universe. What started as an experimental endeavor quickly became the highest grossing film franchise of all-time; racking up $14.7 billion at the box office and counting. Now, DC Comics seems to be playing catch up as starting in 2013, they kickstarted their own DC Extended Universe.

DC coming up with its own major film universe to rival Marvel's own Cinematic Universe has caused friction between the two brands, and has started something of a friendly rivalry at the movies. For that reason, it is rare that we see actors appear in both Marvel and DC films. Although, there have been instances where the DCEU has swooped up actors who failed to get signed to the MCU. Here are just a few instances of prolific actors within the DCEU movie franchise who almost appeared in MCU movies, or other movies that have been adapted from Marvel comic books.

15 RUSSELL CROWE - WOLVERINE

Hugh Jackman's performance as Wolverine is well remembered as, by far, the best thing about the entire X-Men movie franchise, but the role was nearly taken from underneath him by another Aussie native. Director Bryan Singer's first choice for the role was actually Russell Crowe, but when he offered the part to the Oscar winner, he declined due to his misconception that Wolverine was a wolf-lite character.

Since his Gladiator character, Maximus, had a wolf at the center of his cuirass, Crowe thought he would start being typecast as wolf characters. He didn't want everyone of his roles to be "Wolfy the general" or "Wolfy the other bloke." It all worked out in the end as Jackman went on to play Wolverine, and Crowe became Superman's dad, Jor-El, for the DCEU.

14 MARGOT ROBBIE - SUE STORM/INVISIBLE WOMAN

Thanks to her show stealing, breakout performance in The Wolf of Wall Street, Margot Robbie burst onto the Hollywood scene as an instant star. Naturally, Hollywood was so impressed with her work in that film that she was offered dozens of parts in other major productions. One of those productions was for Josh Trank's Fantastic Four movie, where had she accepted the offer would have played Sue Storm, aka The Invisible Woman.

Robbie explained in an interview with The New York Daily News that she declined that offer because she "didn't really resonate with the script...." It proved to be a wise choice on Robbie's behalf, since Fantastic Four went on to tank and her later DCEU role as Harley Quinn was one of the highlights of Suicide Squad.

13 JASON MOMOA - DRAX

Before the character's Jason Momoa is quickly becoming notorious for playing Aquaman for the DCEU, even though the King of the Seven Seas has yet to have his own solo film. His performance as Aquaman isn't too different from how he's delivered himself for other roles (i.e. Khal Drogo in Game of Thrones), which is interesting because his insistent to steer away from what he's done before is why he walked away from Guardians of the Galaxy.

He was once attached to the project to play Drax the Destroyer. There was even concept art made for Drax with Momoa's likeness. As he explained in an interview, he walked away from the role after realizing how similar Drax was to his previous roles. He wanted something new; a challenge.

12 AMBER HEARD - CAPTAIN MARVEL

The once and future queen of Atlantis in the upcoming Aquaman and in a brief appearance in Justice League, we're almost completely positive that Amber Heard's Mera will become the DCEU's next big female character after Gal Gadot's Wonder Woman and Margot Robbie's Harley Quinn from Suicide Squad. And while we've seen a bit of her in the underwater role already, comic books fans across the globe almost saw her as Marvel's Carol Danvers, aka Captain Marvel.

Ultimately, the role went to Brie Larson (and while the verdict is still up in the air, we think it was all for the better) but rumors swirling around the Hollywood water cooler is that Amber Heard was pretty close to suiting up and joining up with the rest of the Avengers as the female powerhouse, as well as starring in Marvel's first feature with a female lead.

11 MICHAEL SHANNON - SPIDER-MAN HOMECOMING

Michael Shannon rarely appears in major mainstream Hollywood productions, but he did just that in 2013 when he played General Zod in Man of Steel. When asked outright in a Fandango interview if he had any interests in appearing in another major franchise, like the Marvel Cinematic Universe, he said no and he was actually offered a role along those lines.

While he refused to specify exactly which film he declined to participate in, he did say it was for a movie that Hollywood has made countless times before. From that description alone, it has been widely speculated that Shannon was offered a part in Spider-Man: Homecoming. If that is true, he was most likely offered the role of The Vulture, which is a villainous role right up Shannon's alley.

10 ADEWALE AKINNUOYE-AGBAJE - BLACK PANTHER

A Marvel Cinematic Universe production of Black Panther was in development for quite some time before it finally hit the big screen in 2018 to box office shattering results. Marvel were developing a Black Panther film for themselves as early as 2009, and Adewale Akinnuoye-Agbaje was in negotiations to play the character. The Oz actor told MTV that year that he was in talks with Marvel for the part and hoped that his recent role in G.I. Joe: The Rise of Cobra could help them "see the potential."

Years later, we would learn that Marvel wanted to go in another direction, with Chadwick Boseman in the lead. Although, Marvel did cast Akinnuoye-Agbaje as Kurse in Thor: The Dark World, the DCEU would later cast him as Killer Croc in Suicide Squad.

9 JOEL KINNAMAN - THOR

Back when Marvel was looking for an actor to play Thor, Joel Kinnaman was hot off the heels of his breakout role as Detective Stephen Holder for AMC's The Killing. Kinnaman hoped to use his newfound acclaim on the small screen by transitioning to mainstream superstardom, so he auditioned for the part of Thor but lost out to Chris Hemsworth. It would take a few years before Kinnaman would have a shot at another superhero franchise and this time, it was for the DCEU.

After Tom Hardy had to drop out of Suicide Squad after being cast as Rick Flag, Kinnaman swooped right in to claim the part for himself. Although he gave a strong performance, Kinnaman told Variety in an interview that Warner Bros. has no specific future plans for Rick Flag and he has no idea if they'll call him back for future DCEU movies.

8 BILLY CRUDUP - BRUCE BANNER/HULK

Back when Ang Lee was still developing his 2003 superhero movie, he always wanted Billy Crudup to play the title role of the Hulk and the monster's split personality, Bruce Banner. Crudup was actually attached to play the part for quite some time. So much, in fact, that concept art was made with Crudup's likeness being attributed to the Hulk character. Before production could start filming, Crudup ended up walking away from the project for unknown reasons and was replaced by Eric Bana.

Crudup would not be seen playing a superhero until 2008's Watchmen, where he played Dr. Manhattan. Most recently, DCEU scooped up Crudup to play Henry Allen, father to Barry Allen, aka The Flash. He played the role in Justice League, and will reprise the role for the Flashpoint adaptation.

7 JARED LETO - DR. STRANGE

Scott Derrickson went through a long and tumultuous road to try and find his title character when it came time to direct Doctor Strange. Originally, Benedict Cumberbatch was cast in the title role, but had to drop out due to scheduling conflicts. The hunt was on for a new Doctor Strange and Derickson met with several actors to see if they were interested, including Joaquin Phoenix, Ryan Gosling, and Jared Leto.

The latter name came the closest to taking the role of Doctor Strange, but before he could snag it, Marvel just decided to push the release date back so that they could get Benedict Cumberbatch. Leto moved on to play The Joker for DCEU's Suicide Squad. Compared to the high praises of Cumberbatch and his film, Leto and his own film received much more unfavorable reviews.

6 ZACHARY LEVI - STAR-LORD

Zachary Levi has already done a bit of flip flopping between Marvel and DC films. First, he took over the role of Fandral from Josh Dallas for Thor: The Dark World. Then, he was cast in the title role of Shazam, which he is currently filming right now. A little before either role came his way, he was in the running to play Star-Lord in Guardians of the Galaxy. It was actually reported in late 2012 that Levi and Jim Sturgess were both the two finalists in the running to snag the part.

Somewhere down the line, Marvel decided to nix them both and instead went with Chris Pratt, who of course won the part. Other contenders to play Peter Quill included Lee Pace, Eddie Redmayne, Michael Rosenbaum, Joseph Gordon-Levitt, Glenn Howerton, and John Krasinski.

5 DOLPH LUNDGREN - CABLE

Last fall, filming on DCEU's Aquaman movie wrapped up and Dolph Lundgren played a supporting role as King Nereus. While Lundgren is no stranger to superhero movies -- he played Frank "The Punisher" Castle back in 1989 -- he hoped to get even cozier to the superhero sub-genre in 2016 when he dipped his hat in the race to play Cable for Deadpool 2.

In a Facebook live session, Lundgren admitted that he was a big fan of the recently released Deadpool movie and he believed that he would make a perfect fit to play Cable in the sequel. Although Lundgren certainly has the look and experience of playing superheroes and his presence would give Deadpool a lot of self aware jokes to spew, FOX ultimately went with Josh Brolin instead.

4 GAL GADOT - NEBULA

In a 2013 interview, Gal Gadot revealed that long before she was ever in contention for Wonder Woman, she was once up for a role in another superhero movie: Guardians of the Galaxy. She did not specifically name the part that she was offered, but she did mention that the role would have required for her to shave her head and be covered in blue paint.

There is only one role in the film that fits such a description, and that's the role of Nebula played by Karen Gillan, who had to shave her head and spend several hours wearing blue paint for the role. Gadot said that she felt uneasy about having to do either, so she politely declined. Considering she went on to play Wonder Woman, it's safe to say everything worked out for the best.

3 WILL SMITH - CAPTAIN AMERICA

When Marvel was looking for an actor to play Captain America in their Cinematic Universe, it seemed like everyone and their mama -- or at least their daddy -- was in the running for the part. Channing Tatum, Garrett Hedlund, Ryan Phillippe, Sam Worthington, John Krasinski, Jensen Ackles, and even Will Smith were either attached to or rumored to play the leader of the Avengers.

With Will Smith, rumors sparked that he'd play the role after Derek Luke -- who ironically later joined the cast of The First Avenger -- spilled the beans in a 2008 MTV interview that he overheard that Smith had been offered the part. In the wake of fan outrage, Marvel announced they never even considered Smith for the part. Smith wouldn't play a superhero (sort of)  until he played Deadshot for Suicide Squad. 

2 PATRICK WILSON - PAXTON

In Ant-Man, Bobby Cannavale played Paxton, the new beau and fiance to Scott Lang's ex-wife, Maggie. Very early in the development of the film, the role belonged to Patrick Wilson. However, due to a scheduling conflict, Wilson had to walk away from the part and the film itself. He was then eventually replaced by Cannavale.

While some fans were disappointed that the Insidious actor had to dip from the production, other fans were relieved because judging from his work as Nite Owl in Watchmen, they would rather seem him play another superhero in a Marvel movie, not a small supporting role. In the DCEU, he provided the voice of the President of the United States in Justice League, and will be playing Ocean Master in Aquaman.

1 DWAYNE JOHNSON - DRAX

Dwayne "The Rock" Johnson came along way from being a professional wrestling WrestleMania headliner. Over a decade years ago, no one would have expected to The Rock to succeed in Hollywood, and lo and behold, he went on to become Hollywood's current highest paid actor. Whenever an action film calls for a towering muscle bound character, The Rock is usually the first actor Hollywood calls on. This was the case when Marvel was looking for a muscle bound actor to play Drax for Guardians of the Galaxy.

The Rock was once in consideration for the role, but for some reason, it never came to fruition. Instead the role went to Dave Bautista, another former WWE wrestler. While he didn't play the superhero, he will be playing a supervillain, Black Adam, in the DCEU.