Sleepless nights over Sandra Bullock's blindfold, says Oscar-winning director

Oscar-winning director Susanne Bier suffered "sleepless nights" after Sandra Bullock refused to cut holes in the blindfold she wore for their horror thriller film, Bird Box, BBC News reports.

Bullock plays a lone mother with two young children, battling an unseen force which compels you to kill yourself if you see it.

Hence the need to constantly wear a blindfold.

The post-apocalyptic film sees Bullock, who plays Malorie, guiding the children down a treacherous river and through a dense forest, all without being able to see a thing. All of this can be seen in the film's trailer, so don't worry, there aren't any spoilers to follow.

But the chances of Bullock disappearing over the side of a boat or into a boggy ditch were definitely higher than Bier would have liked.

She said: "I had a completely dedicated, crazily diligent actor - I said 'can we just make holes in the blindfold?' and she said 'no way, no way'.

"I kept hoping she wouldn't bump into the camera."

Bullock was assisted by an expert who "helps blind people navigate spaces", leaving Bier relieved that the actress "acquired quite sophisticated techniques" for moving around.

Not surprisingly, the Oscar-winning star did still "fall over a number of times", and Bier smiles: "I'm relieved she's still looking good."

Bullock joked as she told Deadline: "It made her very happy when I was blindfolded running into the camera."But the actress said the blindfold didn't just make moving around difficult.

"What's the easiest way as an actor to show how you're feeling on camera? It's your eyes. And you realise when that's taken away you don't know how to act."

Speaking to Reuters, she added: "But I think in the end... it helped give a really jagged feeling to those scenes rather than if I had holes cut in my blindfold and I could see and I was pretending to stumble and be blind."

This film, which depicts Malorie's transformation from reluctant parent into a machete-wielding mother bear, is an unusual take on motherhood.

"It's a portrayal of a very contemporary female heroine," says Bier, who also directed BBC One's hugely successful drama The Night Manager.

"It's a female narrative - defined by women and not men - and is very unconventional in a thrilling, scary movie.

"It's a depiction of motherhood which doesn't fall into the conventions and cliches we've seen in hundreds of films."