Claire Foy's new leading role after The Crown is incredibly disturbing to watch.

The trailer for Claire Foy‘s newest film has dropped and wow, it’s The Queen as we’ve never seen her before.

The actress, best known for playing Queen Elizabeth II in the first two seasons of Netflix’s The Crown, stars in an upcoming horror film called Unsane.

The 33 year old plays Sawyer Valentini in the psychological thriller, a young woman trying to rebuild her life after being forced to move away to avoid a stalker.

“Your life slips away from you, you know? Changing your phone number and your email becomes normal. Taking out a restraining order, normal. Relocating to another city, normal,” she says to a therapist in the opening moments of the trailer.

Everywhere she looks, she sees her stalker’s face.

“I’m alone in a new city and I never feel safe.”

Then things get dark – quickly. After filling in some paperwork, she is taken away by a nurse and ordered to strip down to her underwear. Then she’s told by signing the forms, she’s voluntarily committed herself.

As she tries to convince staff there's been a mistake, she begins to see her stalker everywhere again. The doctor handing her her pills, the doctor coming to check in on her at night.

Then we hear that her mum, who was trying to help get her out, goes missing.

Someone is being stabbed with a knife. Then there's a a murder.

It looks terrifyingly brilliant. Safe to say, this is nothing like The Crown.

Listen: You may have missed it, but The Crown solved a major issue about scones. Post continues after audio.

From director Stephen Soderbergh, who's behind films like Erin Brokovich, the Ocean's Eleven films, Magic Mike and the upcoming Ocean's Eight, the film was shot entirely on an iPhone.

Yes, really.

The film hits Australian cinemas at the end of April.