Ian McKellen had no idea Anthony Mackie was Captain America until they met on set

Anthony Mackie has revealed one of the most memorable moments from filming Avengers: Doomsday, sharing that Sir Ian McKellen offered heartfelt encouragement after discovering Mackie had taken on the mantle of Captain America in the Marvel Cinematic Universe.

Speaking during an interview with IMDb, Mackie recalled meeting the legendary actor on the set of the highly anticipated Marvel film. McKellen, who returns as Magneto after his celebrated performances in the X Men franchise, greeted Mackie warmly before asking what role he was playing in the blockbuster crossover.

According to Mackie, the conversation began with McKellen saying, "Hello, son." Mackie responded by expressing his admiration for the acclaimed actor and his excitement about working alongside him. When McKellen asked about his role in the film, Mackie replied that he was playing Captain America.

McKellen's response immediately stood out to the Marvel star.

"Wonderful... and you deserve that," McKellen told him, prompting Mackie to later thank the veteran actor publicly for his kindness.

The exchange quickly resonated with Marvel fans, bringing together two generations of superhero cinema. McKellen became one of the defining faces of 20th Century Fox's X Men films through his portrayal of Magneto, while Mackie officially inherited Captain America's shield after years of playing Sam Wilson in the Marvel Cinematic Universe. His character completed that journey in Captain America: Brave New World, following Steve Rogers passing the shield to him at the conclusion of Avengers: Endgame.

Avengers: Doomsday marks one of Marvel Studios' biggest crossover productions to date, combining established heroes from the Marvel Cinematic Universe with several familiar faces from the earlier X Men films. McKellen is returning as Magneto alongside Patrick Stewart as Professor Charles Xavier, James Marsden as Cyclops, Alan Cumming as Nightcrawler, Rebecca Romijn as Mystique and Kelsey Grammer as Beast.

On the Marvel Studios side, the ensemble includes Chris Hemsworth as Thor, Sebastian Stan as Bucky Barnes, Paul Rudd as Ant Man, Tom Hiddleston as Loki, Letitia Wright as Shuri, Florence Pugh as Yelena Belova, Vanessa Kirby as Sue Storm, Ebon Moss Bachrach as Ben Grimm, Simu Liu as Shang Chi, Lewis Pullman as Sentry and Robert Downey Jr, who returns to the franchise in a surprising new role as Doctor Doom instead of Tony Stark.

McKellen has also spoken about his experience filming the movie during a recent appearance at a film festival in Rome. Recalling an action sequence directed by Joe and Anthony Russo, he said the filmmakers encouraged him to appear angrier while using Magneto's powers.

The actor explained that he imagined destroying Mar a Lago to channel the required intensity for the performance, recalling that he shouted its name while filming the scene. The anecdote quickly attracted widespread attention following his remarks.

Marvel Studios has positioned Avengers: Doomsday as one of its biggest theatrical releases, with the film scheduled to arrive in cinemas on December 18.