Published Friday, 02 May 2014
The star, who has played Lady Rose MacClare since 2012, has left the show because filming clashes with her promotional duties for live-action blockbuster Cinderella, in which she takes the title role.
The movie is set to be released around Easter next year and Disney bosses have requested that their leading lady makes herself available to help market it worldwide.
Downton Abbey producers will not kill the character off and instead plan to give Lady Rose a reason to be out of sight for the series, in the hope that James will return to the drama in the future.
The sixth series of Downton Abbey is due to air on UTV in the autumn.