Anthony Mackie's casting as the new Captain America in Avengers: Doomsday recently became public when he revealed how actor Ian McKellen reacted upon learning the news on set. McKellen, reprising his role as Magneto, responded with encouragement after Mackie told him about the pivotal role, offering his approval and support for the casting decision. The interaction illustrates a collegial moment between the veteran actor and his younger co-star during production.

Avengers: Doomsday represents an unprecedented Marvel ensemble bringing together major MCU characters alongside X-Men cast members for a team-up against Doctor Doom, portrayed by Robert Downey Jr. in a departure from his Tony Stark character. The film, directed by the Russo Brothers, brings together dozens of actors including Chris Evans, Chris Hemsworth, and returning X-Men stars such as Patrick Stewart and Kelsey Grammer, positioning it as one of Marvel's most ambitious crossover projects to date.