The actor is only following 43 accounts and the MCU stars didn't make the cut.

Forget Thanos snapping away half of the Marvel Cinematic Universe: Marvel fans are up in arms after Robert Downey Jr. did the unthinkable and suddenly unfollowed his fellow Avengers costars on Instagram.

Recently, dedicated fans noticed that Downey—who's followed by 50 million people but only follows 43 accounts—had abruptly stopped following all of his Marvel costars including close friends Chris Evans and Tom Holland. The realization sent fans into a frenzy as they tried to figure out if Downey had some ulterior motive behind his actions, perhaps tied to the fact that after Iron Man's death in Avengers: Endgame, he didn't have any interest in being part of the Marvel Universe anymore.

"I don't know what's happening Mr Stark...WHYYY DID YOUU UNFOLLOW THE MARVEL CAST ON INSTAGRAM?" one fan tweeted, referencing Holland's famous line in Avengers: Infinity War and including an emotional graphic.

Another fan pointed out that Downey changed his header on the account to remove the Iron Man photo he had previously, seemingly adding credibility to the "moving on" theory.

Speculation about Downey's actions immediately sprouted among fans, who wondered if maybe there was some falling out with his castmates. But the real reason may be as simple as Downey—or his manager—trying to downsize and curate his social media now that he's not tied to the Avengers world anymore. The Iron Man actor has been recently using his social media presence to heavily promote the Footprint Coalition, an organization he founded to fight the climate crisis and that its official website describes as "a coalition of investors, donors, and storytellers committed to scaling technologies to restore our planet." He's also been deep in producing new properties with his production company Team Downey, such as the recent Netflix series Sweet Tooth and HBO's Perry Mason.

Avengers: Endgame
'Avengers: Endgame'
| Credit: ©Marvel Studios 2019

Downey does still seem to be following his co-stars on Twitter, indicating that the mass unfollowing doesn't seem to be universal and that, as other fans point out, he may not even be in control of (or know) what is happening on his account.

"I think people are blowing this out of proportion," another fan wrote on Twitter. "RDJ still has a lot of love for his Marvel cast mates, but his manager is the one running his account now and is only focusing on brand stuff/other projects."

A representative for Downey didn't immediately respond to EW's request for comment.

Related content: