Marvel's Avengers: Infinity War has been taking the world by storm. It's catapulted to insane box office success and ushered in a new era for the Marvel Cinematic Universe.

The movie may just be one of the most successful blockbusters of all time. The cast is universally beloved. A few of the movie's directors are, too, for that matter. Yet, if history has taught us anything, it's that there are always secrets lurking behind our favorite pop culture franchises.

Thanks in large part to Marvel's chatty stars themselves, there has been plenty of tea spilled concerning the studio's epic crossover hit.

Some secrets are surprisingly happy ones, like fan favorite directors returning to make sure that their characters remain consistent (we see you, Taika Waititi), while others are decidedly more disturbing, like the time a couple of well-meaning Avengers actors may or may not have accidentally invited a racist family to the premiere of one of the most highly anticipated movies in recent memory.

From Robert Downey Jr. simply refusing to suit up on set to Tom Holland and Mark Ruffalo constantly spilling the beans, here are the 15 Avengers: Infinity War Behind-The-Scenes Secrets That Completely Change The Movie.

James Gunn And Taika Waititi Contributed To The Movie

Everyone loves the characters on screen in a Marvel movie. The actors who portray them are often just as popular, if not more so. Yet, it's becoming increasingly clear that the faces behind the camera are just as well-loved in the Marvel Cinematic Universe.

James Gunn proved himself to be a mainstay in the franchise with his adorable Guardians of the Galaxy characters, even going so far as to write a special Groot script to relay all the tree's thoughts and emotions.

Thor: Ragnarok's Taika Waititi may even outshine his own cast with his hilarious antics and good-natured attitude.

These directors created memorable characters who are instantly recognizable, and the writers of Infinity War, Christopher Markus and Stephen McFeeley, were very aware of that.

To ensure that the characters were consistent throughout the MCU, Markus and McFeeley kept in close contact with Gunn and Waititi to make sure that they were presenting the characters the way that they would be in their solo movies.

Because of this, Gunn and Waititi were directly responsible for their characters' dialogue throughout the movie.

This allowed characters like Thor to retain their newly found humor and wit, to the delight of both actors and fans.

Mark Ruffalo Spoiled The Ending A Year Ago

The world we live in is designed for spoilers. With social media, news blasts, and recap videos, spoilers are basically unavoidable.

To combat this, studios will often send out fake scripts or leak fake test footage to keep fans on their toes. Even with all of this misdirection, though, it's impossible to keep everyone out of the loop, and that's where everything can still go haywire.

With the case of Infinity War's closely guarded secrets, that's exactly what happened.

During an interview last year, Bruce Banner/the Hulk actor Mark Ruffalo let a huge cat out of the bag. While commenting on the occasionally depressing endings depicted in the MCU, Ruffalo teased Infinity War by announcing that everybody passes away.

His co-star, Don Cheadle, who portrays James Rhodes/War Machine, was visibly shocked by this slip. Ruffalo tried to backpedal, claiming that it was, in fact, only half of the cast that perished in the movie.

As we now know, a lot of characters lost their lives in Infinity War. However, these are comic book characters and thus their passing is often but another annoyance in their fight for justice.

Whether or not those demises actually stick or if the characters are resurrected for more solo movies remains to be seen.

Robert Downey Jr. Rewrote His Scenes

Robert Downey Jr as Tony Stark in Iron Man

People like to joke that Robert Downey Jr. doesn't actually act when he portrays Iron Man's alter ego, Tony Stark, especially when it comes to the smug attitude and cocky confidence.

Fans compare Stark's bravado to Downey Jr. himself and constantly come away thinking that the similarities are too obvious to ignore. However, maybe there's a good reason for that.

It turns out, Downey Jr. frequently writes his own lines. The Infinity War directors, the Russo Brothers, were well aware that the actor was intimately familiar with the character in a way that they never could or would be.

Since Iron Man was basically the hero who built the entire MCU, the directors felt that it was super important that the character was represented properly.

To do this, the directors would meet up with Downey Jr. before shooting scenes to let him off of his leash a little bit.

The actor would then rewrite his scenes to better portray his vision of his iconic character.

Joe Russo described the atmosphere of the Infinity War set as that of a "highly collaborative think-fest." Both the directors and the writers were very dedicated to portraying the characters properly and were not too proud to seek advice from others who had been in the MCU longer.

Deadpool's Rejection Letter

Deadpool isn't above giving his fellow heroes a hard time. Ryan Reynolds is more than happy to do the same for his fellow Marvel actors, too.

So, instead of congratulating the cast of Infinity War for their record-breaking movie, Reynolds did what he does best and gently mocked his Marvel alums.

Reynolds did actually congratulate the cast on their success. He commended their tenacity and perseverance. Reynolds said that they were the sorts of people who never give up, and neither does he.

However, perhaps that was a bit of a backhanded compliment? Because the Tweet was accompanied by a photo of rather brutal rejection letter addressed to Deadpool from none other than Tony Stark himself.

In the letter, Stark very simply and succinctly refuses to induct Deadpool into the Avengers team. Stark gives Deadpool a flat-out "no" without any reason or explanation as to his failure to join the team.

It is then suggested that he try his luck with the X-Men... but it's pretty clear how that one is likely to go down.

It's easy to see why the Avengers would have their doubts about the Merc with a Mouth-- he may be even more difficult to control the Hulk. However, maybe his presence and unpredictability would have been useful in the battle against Thanos.

Elizabeth Olsen Hates Her Low-Cut Costume

Scarlet Witch MCU

For the most part, the MCU does a pretty good job of making sure that their female heroes are well-covered. They are often dressed just as modestly, if not more so, than male characters of the franchise.

However, Scarlet Witch/Wanda Maximoff actress Elizabeth Olsen couldn't help but notice one key difference between her own costume and her fellow castmates'.

Scarlet Witch showed off quite a bit more skin than the rest of the female Avengers, and Olsen wasn't very happy about it.

Olsen revealed that she wished that her super suit was a little less, well, revealing. Though she is mostly covered in the movie, Scarlet Witch's outfit does show off quite a bit of cleavage, which makes Olsen a little uncomfortable.

The actress admitted that she had noticed that her co-stars, Tessa Thompson and Scarlett Johannsen, had costumes that did not show off nearly as much cleavage as hers did and she wished she had been afforded the same luxury.

However, Olsen did note that the comic book version of her character's ensemble, which is a bright red leotard with an upside-down "W" for a headband, was "so horrible." The actress did appreciate that she at least didn't have to wear that outfit.

Robert Downey Jr. Refused To Wear A Mocap Suit

When you're Robert Downey Jr., you get to do whatever you want. That's not hyperbole, it's a fact.

Many fans of the Marvel Cinematic Universe credit Iron Man with its multi-franchise success, and many Iron Man fans credit Downey Jr. with making Tony Stark the pop culture icon that he is today.

So, perhaps the 53-year-old actor can't be blamed for using some of that popularity to his own advantage. Downey Jr. uses his status as an OG Avenger to get out of the most miserable aspects of being on set.

He completely refuses to wear those uncomfortable motion capture suits... and even just his Iron Man pants.

During a set visit, Downey Jr. revealed to Digital Spy that he wouldn't "be caught" in a motion capture suit.

Obviously, a lot of CGI and special effects go into any given Marvel movie. However, you would have to assume, with its grand scale and its large number of heroes, that this fact would go double for Infinity War.

However, Downey Jr. still refused. While his co-stars, like Peter Parker/Spider-Man actor Tom Holland, were geared up, Downey Jr. would simply wear just the top half of his Iron Man suit. Even his Iron Man pants were added in with the help of CGI.

Dave Bautista Doesn't Know What He Did In The Movie

Dave Bautista as Drax in Guardians of the Galaxy

Dave Bautista plays the stone-faced, takes-everything-too-literally Drax. He was first introduced in Guardians of the Galaxy, but also appeared in Infinity War. Things didn't feel any different for Bautista, though.

The actor said that it didn't even feel like he was visiting another franchise's set. In fact, to Bautista, it felt as though the Avengers were guest-starring in a Guardians movie, instead.

Due to the nature of the movie, Bautista was still mostly filming with the Guardians cast, with a couple other Avengers actors thrown in. So, it didn't actually feel like the giant ensemble movie that it actually was.

Both Infinity War and the upcoming fourth Avengers movie were shot at the same time. So, Bautista would show up for work knowing his lines, he would do his job, and go home.

However, aside from that, he really had no idea what was going on.

At any given time, he could have been shooting for Infinity War or for the sequel, and he couldn't really keep track of which one he was filming.

So, the Drax actor knows quite a lot about his character's story arc over the two movies, but he has no idea what actually happens in either one.

Elizabeth Olsen Was Badly Photoshopped On A Magazine Cover

Most actors have to deal with their bodies being photoshopped, unfortunately. It's basically standard procedure in the industry.

Busts are enlarged, muscles are given more definition, wrinkles, stretch marks, and bags under the eyes are removed. It can be rather insulting and many stars are quick to point out their discomfort with the practice.

Some even go as far as to display their real bodies alongside the photoshopped version. For Infinity War's Elizabeth Olsen, however, it was her face that got chopped up by some photo-editing software.

Olsen was featured in a series of Infinity War covers for Empire Magazine-- well, sort of, the face on the cover was definitely not her face.

The actress noticed the bizarre likeness and posted the cover on social media, asking fans if the photoshopped result actually looked like her. Olsen's followers agreed that the Scarlet Witch featured on the magazine most definitely did not look like the real deal at all and called out the magazine for distorting the actress' image.

Empire later said that they had not done anything to alter the image. Olsen ultimately deleted her posts, but it was already quite clear that her followers were all on her side in this bizarre incident.

The Actors Didn't Even Know The Movie's Plot While Shooting

Marvel is willing to go to great lengths to keep spoilers a secret from its audience-- even if it means keeping them a secret from their own cast.

All of the cast, new actors and long-standing stars alike, were kept in the dark on the twists and turns that Infinity War held in store. The large cast all reacted in wildly contrasting ways, of course.

For Don Cheadle, the mystery was all just part of the fun. The actor revealed that he actually preferred not knowing what was going to happen in the script. He liked learning about key plot points as they were happening, almost the way a fan might learn through watching the movie.

However, like it or not, these steps were necessary. Some of the actors simply could not be trusted to keep the biggest spoilers a secret.

Take Tom Holland, for example. The Spider-Man actor has such a bad habit of spilling the beans that Marvel had to assign Doctor Strange actor Benedict Cumberbatch to babysit his young colleague during interviews.

Holland was also not given access to the entire script while filming and didn't even know about his own character's biggest scene until it came time to shoot it.

Chris Pratt Got Backlash For Sending Prayers To Kevin Smith

Chris Pratt in Guardians of the Galaxy Vol. 2

It seems like a simple little thing. If you're a religious person, and someone you know just had a bad health scare, you would possibly let them know that you're praying for them.

It should be no different than keeping someone in your thoughts. However, for Peter Quill/Star-Lord actor Chris Pratt, that wasn't quite the case.

When comic book fan/director/expert Kevin Smith had a bad heart attack scare recently, Pratt opened up his heart and let Smith know that he was in his prayers.

The Infinity War actor was only one of many in the industry who showed their support for Smith. However, he received massive backlash over his kind words.

Pratt wasn't pushy or rude about his beliefs, nor did he say anything about Smith's beliefs. He was just showing concern for a fellow industry professional.

However, Twitter users unleashed on Pratt, saying that he could find more useful ways to support Smith than simply praying for him. 

Guardians of the Galaxy director James Gunn defended Pratt. Gunn made it clear that Smith can handle his own medical bills and that Pratt does not owe the actor anything more than his kindness, which he had already tried to impart.

Tom Holland Accidentally Leaked The Poster

Mark Ruffalo made waves when he infamously live-streamed a good chunk of the Thor: Ragnarok premier over his Instagram account by accident.

However, he wasn't the only Avenger to make such a mistake. Spidey actor Tom Holland did basically the exact same thing.

Thankfully, it was just a poster that was leaked this time.

Holland is famously bad at keeping spoilers under wraps. This is why Marvel eventually just stopped giving the young actor access to those secrets altogether.

Holland went on Instagram live to stream an unboxing video of a package he supposedly got from none other than his Infinity War co-star, Ruffalo. Inside the box, there just so happened to be a previously unrevealed poster for the movie.

Holland seemed to be shocked at his mistake and turned off his stream right away. It's very likely that the whole thing was just a joke, seeing as how the "leak" was conducted by two of the allegedly biggest leakers in the entire Marvel Cinematic Universe. Add to that the fact that Marvel released the poster soon after.

However, then again, maybe these two really are that bad at keeping a secret and the studio was forced into doing some major damage control.

Joe Russo Says It's Impossible To Include The Defenders In A Crossover

Marvel has pretty much made up their minds that they will not be crossing their TV shows over with their movies. Sure, there is the occasional reference, the Netflix shows love to bring up "the incident" in which the Avengers destroyed New York while trying to save the city from the Chitauri.

However, most of the time, that's the farthest that these Easter eggs ever go. One character says one line that sort of brings up one scene in a movie and that's the end of it.

According to Infinity War director, Joe Russo, that's all it's ever going to be.

Russo did admit that a crossover between Netflix's Defenders and the MCU's Avengers had been considered. 

However, the director felt that it was already difficult enough keeping up communication between all the different Marvel movie directors without adding the TV showrunners into the mix.

In the end, Russo decided a crossover between the TV characters and the Infinity War characters was "practically impossible " and decided to focus on the movie characters alone.

Other fans have obviously wondered when Marvel would acknowledge their popular network show, Agents of Shield. Daisy actress Chloe Bennett has been vocal about her displeasure over her series being left out of the crossover fun.

Chris Hemsworth Worried Thor Would Go Back To Being Serious

When Chris Hemsworth first brought Thor to life, he was a big, hulking lug who loved his mead and his hammer. The God of Thunder was a total fish out of water who didn't understand the Avengers' customs, methods, or jokes.

Flash forward to Thor: Ragnarok and the short-haired and even shorter sleeved Norse God can now quip with the best of them. He certainly has come a long way, which is exactly why Hemsworth was so protective of his alter ego while shooting Infinity War.

Before he ever showed up on set, Hemsworth made sure to make one very important request of the Russo Brothers: he asked them not to make Thor serious again.

Hemsworth told his new directors that he wanted to keep Thor light and fun, the way he had been portrayed in Ragnarok thanks to director Taika Waititi's bubbly sense of humor.

It's a fair request. It must be more enjoyable for the actor to portray a lighthearted character and Ragnarok was a huge success.

It seems quite obvious at this point that the Russo Brothers were more than happy to comply, seeing as how they went ahead and got Waititi to help develop his characters for their script.

The Keaton Jones Backlash

Keaton Jones became an internet phenomenon when a video turned up of the young boy crying and lamenting the bullying that he was forced to endure at the hands of his peers.

In the video, Keaton asked why bullies do what they do. The boy felt that people who are different should not be ridiculed or treated badly for something that, most of the time, they likely can't control.

Steve Rogers/Captain America actor Chris Evans happened across the video on social media and graciously extended an offer for Jones to attend the Infinity War premiere.

Incredible Hulk actor Mark Ruffalo later reached out to Jones and his family, as well. This should seem harmless, but, of course, everything backfired in the end.

Reports later accused Jones' family of being racist. Photos turned up of the family with an actual Confederate flag. Jones' mother did not deny the photos, but she did say that they did not automatically make her family racist.

Jones said that her family has often been mistreated because they were not racist. Confederate flags were the center of a lot of controversies last year, as many businesses stopped selling them and many local governments began taking them down along with Confederate statues.

Marvel Has Nothing To Do With The Sony Spider-Man Movies

Tom Holland's geeky Spider-Man is one of Marvel fan's best-loved characters right now. Holland's real-life geekiness and innocence certainly help, too.

Marvel has had a string of hits lately. Thor: Ragnarok and Black Panther were giant successes, and Infinity War is somehow leaving both movies in the dust.

However, it turns out that the success of Spider-Man: Homecoming has nothing to do with Marvel's talented writers and directors. In fact, it was all thanks to Sony.

According to Kevin Feige, Sony's plans for the web-slinger have nothing to do with Marvel's plans. Though the Sony movies are very obviously connected with the MCU, and the two studios made a historic deal that would allow the character to be used in by both, they don't actually collaborate all that much.

Sony is developing the three Spider-Man movies, the Venom spinoff, and the Black Cat movies all on their own, with their own plans in mind.

As for why Sony has not been involved in Marvel's use of Spider-Man, Feige said that the studio had had their own plans for Peter Parker-- and it's pretty clear what he meant by that

This also explains how Infinity War was able to use Spidey in such a heartbreaking manner without jeopardizing any of his highly anticipated sequels.

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Can you think of any other behind-the-scenes secrets that fans need to know about Avengers: Infinity War? Sound off in the comments!