Nearly 20 years in, The Marvel Cinematic Universe continues to surprise fans with new projects that arrive in theaters and streaming with a Disney+ subscription. Plenty of incredible talent continues to join the fun, with Sadie Sink debuting as Jean Grey in Spider-Man: Brand New Day. A new rumor claims another Stranger Things star might be joining the shared universe, and I think they'd be perfect.
After her Spider-Man role, Sink will return as Jean Grey as part of the developing X-Men movie's cast. While we'll have to wait until 2028 for that title to hit theaters, but a new Marvel rumor claims that Millie Bobby Brown might be appearing in an upcoming Marvel movie. This claim comes to us from the Twitter of scooper HTTSH, which posted simply:
Milly Bobby Brown is now in serious talks to join the MCU.
I mean, how awesome would this be? Millie Bobby Brown was basically a superhero during her tenure as Eleven in Stranger Things (especially in the final season), so she seems like a great choice to play a comic book character in the MCU. And if she does, she'll join both Sadie Sink and David Harbour as ST actors who pivoted over the MCU.
Of course, this is just a rumor at this point, one of countless ones currently circulating the shared universe. I'm taking it all with a grain of salt for the time being, but the timing seems right. Brown's schedule should be freed up after Stranger Things' finale, and she's proven herself capable of doing action sequences from her time playing both Eleven and Enola Holmes.
Of course, David Harbour was the first one to join the fun, debuting as Red Guardian in Black Widow before reprising his role in Thunderbolts*, What If...?, and as part of the Avengers: Doomsday cast. It should be fun to see if/when he crosses over with Sink's Jean Grey, with the breakout stars now playing very different characters than their Stranger Things counterparts.
Millie Bobby Brown is arguably the biggest breakout star of Stranger Things, becoming a household name at a young age thanks to her heartbreaking performance in Stranger Things' first season. The audience watched her grow up before our eyes during the show's run from 2016-2025, and during that time she also took major gigs with genre work including Godzilla, Damsel, and Electric State. This, compared with her ongoing popularity, makes Marvel potentially casting MBB seem like a no-brainer. We'll just have to see if this rumor ends up actually being legit.
The next Marvel movie hitting theaters (and featuring David Harbor) is Avengers: Doomsday on December 18th as part of the 2026 movie release list. As for Millie Bobby Brown, she recently celebrated the release of Enola Holmes 3 on Netflix.
