( EW.com ) -- It 's a casting `` X '' -gravaganza ! Director Bryan Singer tweeted Tuesday that Ian McKellen and Patrick Stewart will be reprising their respective roles as Magneto and Prof. X in `` X-Men : Days of Future Past , '' and they 'll be joined by `` X-Men : First Class '' stars Michael Fassbender as Magneto and James McAvoy as Prof. X . Wait , what ? For the geek uninitiated , `` Days of Future Past '' is also the title of an X-Men comic book storyline from 1981 , which alternated between a dystopian future in which mutants are living in internment camps , and the present day mutants working to prevent that future from happening . EW.com : Bryan Singer will direct ' X-Men : Days of Future Past ' With this casting news , Singer has all but confirmed that the next X-Men film will reconstitute that storyline a bit , making the Fassbender/McAvoy mutants in the go-go 1960s the `` present day '' storyline , and the McKellen/Stewart mutants in the early 21st century the ones trapped in a bleak alternate future . This is likely a way back to the series for Stewart , given that his Prof. X was ( more or less ) killed off in 2006â€²s `` X-Men : The Last Stand . '' Curiously , Singer also officially announced that `` X-Men : First Class 's '' Jennifer Lawrence and Nicholas Hoult are also returning as Mystique and Beast , respectively . Does this mean Rebecca Romijn and Kelsey Grammer will be playing their 21st century counterparts ? All Singer would say in his final tweet : `` More to come ... '' EW.com : All time great comic book movies . This also officially means that McKellen is set to go up against himself : Both `` X-Men : Days of Future Past '' and `` The Hobbit : There and Back Again '' are scheduled to hit theaters on July 18 , 2014 . Geek brains are exploding everywhere . See the full story at EW.com . CLICK HERE to Try 2 RISK FREE issues of Entertainment Weekly . © 2011 Entertainment Weekly and Time Inc. All rights reserved .
Ian McKellen and Patrick Stewart have been cast in `` X-Men : Days of Future Past '' McKellen will reprise his role as Magneto and Stewart will be back as Prof. X. Michael Fassbender and James McAvoy of `` X-Men : First Class '' will also portray Magneto and Prof. X . The casting news hints that the next film will reconstitute a 1981 comic book storyline .