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The British actress is in negotiations to play Emma Frost, a telepathic mutant whose allegiances are unclear, reports Deadline.
The 'She's Out Of My League' star was rumoured to be in the running to play Peggy Carter in the upcoming Captain America film before the role was eventually given to Hayley Atwell.
Kick-Ass's Matthew Vaughn will direct X-Men: First Class. Filming starts in London this summer.
