
Two major movie stars made a surprise appearance at the premiere of Thunderbolts*, leading many to speculate that they both could be debuting in the MCU at any time. The world premiere of Thunderbolts* recently took place, and attendants were treated to seeing multiple stars from the film on the red carpet, such as Florence Pugh, David Harbour, and Julia Louis-Dreyfus. However, some surprise guests who were not cast in the film (or the MCU) also made appearances.
Hollywood stars Nathalie Emmanuel (Game of Thrones) and Jodie Turner-Smith (Queen & Slim) surprisingly attended Thunderbolts* world premiere in London, England on Tuesday, April 22, despite not being in the film or the MCU. This led to many fans speculating on whether Emmanuel and Turner-Smith will be cast in the MCU at some point in the near future, as they were the only non-MCU cast members at the premiere. The two actresses joined other Thunderbolts* actors and other MCU names (such as Pedro Pascal and Simu Liu) on the red carpet.

Marvel Studios currently has a lot of projects in the works or on its upcoming slate that will need cast members (such as X-Men projects), so rumors will likely continue to run wild regarding Emmanuel and Turner-Smith's appearances at the Thunderbolts* premiere, even if those rumors are shot down by the actors.
Emmanuel and Turner-Smith have both been popular fan-castings for the MCU's version of Storm, a role that was previously synonymous with Halle Berry. A reboot X-Men film is already planned at Marvel Studios, and since Storm is such a vital member of the team, the studio will likely feature her in the film.
Many fans have already begun to speculate on social media that Emmanuel and Turner-Smith's appearance at the Thunderbolts* premiere could indicate that they will both be in X-Men. The most popular theory is that the pair will bring Storm and Rogue to life. However, it is important to keep in mind that no official casting announcement from Marvel Studios has been made.
Will Nathalie Emmanuel and Jodie Turner-Smith Eventually Join the MCU?

It is not uncommon for actors to attend movie premieres even if they were not cast in that particular movie or franchise. Some premieres invite different actors, musicians, influencers, and general celebrities to experience the film.
However, the fact that Emmanuel and Turner-Smith were the only non-MCU actors at the Thunderbolts* premiere is enough to raise an eyebrow, especially considering the two have been mentioned in many fan castings.
The pair's appearances at the premiere are worth keeping an eye on. There's nothing wrong with speculating that something with more substance may be going on behind the scenes. However, fans won't know anything for certain until Marvel Studios or an actor makes an official announcement.
It is worth noting, though, that Avengers: Doomsday and Avengers: Secret Wars are just around the corner. Those movies have already been confirmed to feature the X-Men in a major way. So far, Marvel Studios has announced that multiple X-Men actors who played in Fox's films would be in Doomsday (such as Ian McKellen, Patrick Stewart, and James Marsden).
It is possible that Marvel Studios could also introduce some new X-Men members into the fold in Doomsday or Secret Wars. However, it is equally as likely that any new faces for X-Men characters will be saved for what will likely be the Mutant Saga that takes place after Secret Wars.
For any rumors that believe the two actresses appearing at the Thunderbolts* premiere mean they are in that film, it is safe to assume that they are not. Being such major actors, they likely would have been announced sometime during the film's production.
Most notably, Turner-Smith will be seen next in Tron: Ares and A Big Bold Beautiful Journey. Emmanuel's next acting credit will come in Fast X: Part 2.
Thunderbolts* has received incredibly high reviews, with some even calling it the best movie since Avengers: Endgame. The film will be released on Friday, May 2, and stars Florence Pugh, Sebastian Stan, David Harbour, and Julia Louis-Dreyfus.