X-Men: Dark Phoenix marks the end of Fox's mutant saga, with the rights to the studio's Marvel characters reverting back to Disney. Dark Phoenix likely marks the final performances of James McAvoy and Michael Fassbender as Professor Charles Xavier and Magneto, respectively. The two actors first appeared together as their iconic characters in X-Men: First Class eight years ago, and shared the screen in three more films. McAvoy has now revealed his favorite Fassbender performance was in the first film they worked on together.

"My favorite performance of his is definitely First Class," McAvoy told Rotten Tomatoes. "It was a great film balancing an ensemble, giving everybody an arc and stuff, but in terms of who that film is really about, that was the origin story for Magneto. And just getting to see him rock this, not just mutant leader figure, which he wasn't yet, but actually imbue it with a sort of James Bond, espionage, spy-like quality as well. Like that was just a wicked thing to do with your character."

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Fassbender, however, was quick to graciously give First Class director Matthew Vaughn credit for his take on the character. "A lot of that was Matthew as well, gotta say."

"Yeah but you had the style, the chops, and the gear and the silhouette to carry that shit off beautifully," McAvoy continued. "That was a tall order, you know what I mean? You don't expect that with an X-Men movie, and you really subverted what it was to be in an X-Men movie."

Vaughn's X-Men: First Class was released in 2011 and served as a new starting point for the Fox franchise. Recently, the director revealed he had an elaborate plan for a First Class trilogy that would have culminated with Days of Future Past. However, the studio instead opted to move right ahead with the past/future X-Men mash-up movie, something that prompted Vaughn to depart the franchise.

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Directed and written by Simon Kinberg, Dark Phoenix stars James McAvoy, Michael Fassbender, Jennifer Lawrence, Nicholas Hoult, Sophie Turner, Tye Sheridan, Alexandra Shipp, Kodi Smit-McPhee, Evan Peters and Jessica Chastain. The film is out in theaters now.