Iain Glen's latest film 'My Cousin Rachel' will keep you ''guessing''.

The 'Game of Thrones' star is starring alongside Rachel Weisz, 47, in the new film by Roger Miller which is based around the 1951 novel by Daphne Du Maurier and Iain, who plays Nick Kendall, says the story will ''keep you guessing'' in a good way.

Speaking to website Collider, the 55-year-old actor said: ''Your relationship to Rachel, played so brilliantly by Rachel Weisz, changes throughout. You become entranced and enticed by this exotic creature that comes in and turns things upside down and you spend the rest of the film thinking 'I've got a hold of it. I know what's going on. Wait, no I don't.' That's the psychological thriller that's at the heart of Daphne Du Maurier's writing.''

The film follows young Englishman Philip (Sam Claflin) who plots revenge against his mysterious cousin Rachel believing that she murdered his guardian.

But his feelings become complicated as he finds himself falling under the beguiling spell of her charms and Iain claims the audience will also jump between liking the character and not trusting her.

Iain said: ''I knew that she was the great mistress of irresolution where nothing would become concrete and you'd be suspended throughout.

''But in amongst that you feel like you understand and that you've just been given a clue which leads you to one conclusion.

''But then before you know it, you're being dragged back into another conclusion. Rachel does that very well because you feel for her at times.

''You feel her hurt sometimes, and then you feel her vulnerability but then you think she's being manipulative.

''She plays it out very subtly throughout so that you're kept guessing.''