January Jones has officially signed on for the role of Emma Frost in Matthew Vaughn's X-MEN ORIGINS: FIRST CLASS, reports VARIETY. Previously it was reported that Alice Eve (SHE'S OUT OF MY LEAGUE) would play the part.

The MAD MEN star joins James McAvoy, Michael Fassbender, Kevin Bacon, Rose Byrne, Edi Gathegi, Nicholas Hoult, Caleb Landry Jones, Jennifer Lawrence, Oliver Platt, Lucas Till and Jason Flemyng.

Also new to the cast are Bill Milner (SON OF RAMBOW) as a young Magneto and Morgan Lily (2012) as a young Raven.

The film, which starts production at the end of month in London, follows the early years of Prof. X and Magneto starting the school for gifted students.