For the film prequel, a number of newcomers have joined the popular franchise, including James McAvoy, January Jones, Michael Fassbender and Kevin Bacon.
James stars in the film as a young Professor Xavier, with Inglourious Basterds' actor Michael taking on the role of Magneto.
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Mad Men's January is cast as telepathic Emma Frost, Skins actor Nicholas Hoult plays the Beast and Kevin stars as supervillain Sebastian Shaw.
The film is directed by Kick Ass' Matthew Vaughn and has been set in the 1960s, with references to the lives of Martin Luther King and Malcolm X.
According to 20th Century Fox, the plot is as follows: "Before Charles Xavier and Erik Lensherr took the names Professor X and Magneto, they were two young men discovering their powers for the first time.
"Before they were archenemies, they were closest of friends, working together, with other Mutants (some familiar, some new), to stop the greatest threat the world has ever known.
"In the process, a rift between them opened, which began the eternal war between Magneto's Brotherhood and Professor X's X-Men."