Jennifer Ehle and Kit Harington are to star in the Spooks film.
The Zero Dark Thirty actress and the Game Of Thrones star have both signed up for the big screen adaptation of the hit BBC spy series, according to Screen Daily.
The movie, to be directed by original series director Bharat Nalluri, sees Harry blamed when terrorist Adam Qasim escapes from MI5 custody. Harry then disappears and his protege Will Crombie (Kit) is tasked with finding out what happened.
Jennifer will star as Dame Geraldine Maltby of MI5.
Production is due to start early in 2014.
The BBC series ran for 10 series from 2002 to 2011 and scooped several accolades including a Bafta for best drama series and Royal Television Society Awards.