Credit: Marvel ComicsMarvel fans might want to brace themselves, because an MCU actor may have just slipped up in a way that nobody at Marvel Studios is going to love.
And it wasn’t a tiny little “oops” either.
It was the kind of comment that instantly made fans start connecting the dots, rewatching interviews, and wondering if one of Avengers: Doomsday’s biggest surprises had just been exposed way earlier than planned.
Of course, Marvel is famous for keeping everything locked down. Actors dodge questions, interviewers get shut down, and half the cast usually pretends they don’t even know what movie they’re filming.
But this time, one familiar face may have accidentally given away a significant clue about what kind of chaos is coming.
And if the quote means what fans think it means… Doomsday could be even bigger than anyone expected.
Avengers: Doomsday Is Already Packed With Confirmed Heroes
Marvel Studios has been building toward Avengers: Doomsday as the next massive crossover event, and the confirmed cast list already feels almost unreal.
We’re not talking about a small Avengers reunion. We’re talking about Marvel pulling characters from across the MCU and stacking them into one film like it’s the final chapter of an era.
Fans already know the movie will include major returning heroes, and Marvel has confirmed several key names tied to the project.
That includes Professor X (Patrick Stewart), Magneto (Ian McKellen), Beast (Kelsey Grammer), Gambit (Channing Tatum), Nightcrawler (Alan Cumming), Mystique (Rebecca Romijn), and Cyclops (James Marsden).
On top of that, Marvel has also confirmed that Shuri (Letitia Wright) will be involved, and it’s hard to imagine a world where Thor (Chris Hemsworth), Loki (Tom Hiddleston), Sam Wilson (Anthony Mackie), and Steve Rogers (Chris Evans) don’t have major roles as well.
At this point, Doomsday is shaping up to be the biggest Marvel cast ever assembled.
And it’s clear Marvel is setting the stage for something much larger than a standard Avengers story.
The X-Men Are Finally Becoming a Main MCU Force
For years, Marvel treated the X-Men like a separate corner of the superhero world. Fans watched them exist in their own franchise, timelines, and universe.
But Avengers: Doomsday looks like the moment Marvel finally stops treating mutants like a side story.
Professor X (Patrick Stewart) is back.
Magneto (Ian McKellen) is back.
Beast (Kelsey Grammer) is back.
And Marvel is also bringing in Gambit (Channing Tatum), Nightcrawler (Alan Cumming), Mystique (Rebecca Romijn), and Cyclops (James Marsden).
That list alone feels like a movie event on its own.
And on top of all that, fans also expect Wolverine (Hugh Jackman) to appear, even though Marvel hasn’t officially confirmed him yet.
If this cast lineup holds, then Marvel isn’t just bringing mutants into the MCU. Marvel is making them central to the story.
And that has enormous implications for what kind of conflict Doomsday might be building toward.
Rumors Suggest the Fantastic Four and Mutants Might Clash
With Marvel also introducing the Fantastic Four into the MCU, fans have started wondering whether Doomsday will begin with heroes… not exactly acting like heroes.
There’s been growing chatter that the Fantastic Four and the X-Men could actually clash early in the film. Not a friendly misunderstanding. A real conflict.
And honestly, it makes sense.
These are two massive teams with entirely different backgrounds. If they come from different universes or timelines, they might not trust each other at all.
Marvel has done this before. Captain America: Civil War proved that superhero-on-superhero action is one of the studio’s favorite ways to kick off a significant story.
So the idea of Fantastic Four vs. X-Men isn’t just fan wishful thinking.
It feels like the kind of chaos Marvel would absolutely build into a Multiverse movie.
And now, thanks to one actor’s comments, fans think that rumor may be closer to the truth than Marvel wanted.
Alan Cumming Hints at More Than He Should Have
Nightcrawler actor Alan Cumming recently addressed earlier comments he made about the X-Men possibly fighting the Fantastic Four in Avengers: Doomsday.
While appearing on Jimmy Kimmel Live!, Cumming talked about working with Fantastic Four star Pedro Pascal and mentioned that Pascal apparently got hurt during a fight scene.
That alone raised eyebrows.
Then things got even more interesting when Kimmel asked whether the two actors were fighting. Cumming responded by saying he “wasn’t fighting,” and instead described it more like he was “just sort of… being.”
That is an extraordinary answer.
And Marvel fans immediately noticed that he didn’t deny that something happened. He just changed how he described it.
Which is precisely the kind of vague wording that sends Marvel fans into full conspiracy mode.
His Comments Don’t Match What He Said Before
What makes this even more suspicious is that Cumming has already hinted at a Fantastic Four vs. X-Men situation before.
Back in May 2025, he told BuzzFeed UK that he was learning fight choreography for his return to Marvel, and he specifically joked about hitting Pedro Pascal in the head.
That comment led fans to assume Nightcrawler and Mr. Fantastic would end up in a fight.
Then, in July 2025, Cumming and Pascal leaned into the rumors even more. When Cumming filled in for Kimmel and interviewed the cast of The Fantastic Four: First Steps, the two actors joked around and directly stated, “Alan and I have never been in a fight.”
It sounded like damage control. Or maybe it sounded like Marvel stepping in behind the scenes.
Now, with Cumming circling back and saying he “wasn’t fighting,” fans are convinced he’s trying to walk it back without outright denying it.
Even more interesting? As of early 2026, neither Cumming’s Nightcrawler nor Pascal’s Mr. Fantastic has appeared in major marketing for Doomsday.
Marvel has kept their roles quiet, which only makes the speculation louder.
The X-Men and Fantastic Four Will Likely Drive the Plot
Even with a remarkably stacked cast, it’s becoming clear that the X-Men and Fantastic Four will play huge roles in the story.
This marks the first time the X-Men have ever been positioned as major players in an Avengers movie. That alone makes Doomsday feel like a turning point.
And if Doctor Doom truly serves as the main villain, then the Fantastic Four become absolutely essential. Doom isn’t just a random threat. He’s tied to their world.
Marvel also has another advantage here: both teams already connect to Multiverse storytelling.
Reed Richards is rumored to have deep knowledge of other universes in The Fantastic Four: First Steps. Meanwhile, Beast (Kelsey Grammer) already showed up in The Marvels, where he analyzed Monica Rambeau after she crossed into his universe from Earth-616.
That means these characters aren’t starting from scratch. They already have pieces of the Multiverse puzzle.
So when fans imagine Doomsday turning into a multiversal collision course, the X-Men and Fantastic Four feel like the teams most capable of understanding what’s happening.
Whether Cumming is telling the truth or playing Marvel’s secrecy game is still unclear.
But one thing is obvious: Marvel fans are now watching every interview like it’s a crime scene investigation.
Marvel’s Biggest Mystery Just Got Even Bigger
Marvel Studios may want to keep Avengers: Doomsday under wraps, but interviews like this make that almost impossible.
Alan Cumming’s shifting comments have only fueled speculation that the X-Men and Fantastic Four could collide before they unite.
And if that happens, it would make Doomsday far more than a standard Avengers team-up.
It would be a Multiverse power struggle, a clash of legacies, and possibly the most significant crossover Marvel has ever attempted.
For now, fans can only do what they always do best: overanalyze everything… and wait for Marvel to show its hand finally.