The Voices – one of films selected for the O2’s Sundance London Film Festival last weekend – features Ryan Reynolds, talking pets and the severed head of Gemma Arterton.

By director Marjane Satrapi’s own admission, the script was “so f***ed up, I had to do it”. She spoke to PATRICK GRAFTON-GREEN.

The Voices tells the story of Jerry (Ryan Reynolds), a schizophrenic man-child who accidentally kills his date for the night (Gravesend’s Gemma Arterton) and in the aftermath confides in his dog Bosco and cat Dr Whiskers.

The pets not only talk back, but start making suggestions about what to do next.

For Iranian director Marjane Satrapi, best known for her outstanding debut, Persepolis (2007), this is a first English language film, and the first she hasn’t written herself.

Penned by Paranormal Activity 2’s Michael R. Perry, it was the oddball nature of The Voices that drew her in.

She said: “I read the script and it was a delight. I started reading it and I couldn’t put it down. At the end I thought: ‘Oh my God this is so f***** up’.

“Then I slept and in the morning, I remember it very well, I was brushing my teeth and I looked at myself and my brain was like: ‘It’s so f***** up that I have to do it’.

“How come there is this guy who is a killer, a psychopath who kills a woman and chops her into pieces, how come I like him? How am I going to make it? How am I going to make people like this guy, because when you do these things people normally don’t like you?"

Reynolds, who has been in a series of flops in recent years (Green Lantern, The Change-Up, R.I.P.D), is not an actor who immediately springs to mind when considering the lead role.

He has, however, received acclaim for his performance – also voicing his character’s benevolent pet dog, foul-mouthed Scottish cat and the character ‘bunny monkey’ as well.

Explaining her choice of lead, Satrapi said: “Ryan Reynolds is like a Ferrari but people see him as if he is a Peugeot. He has a range.

“When I met him I didn’t know he was that talented because I know him like everyone else.

“He is extremely talented.

“You know how it is, you do one thing and people think this is this a nice guy, romantic comedy, beautiful chest. But he is much more than a beautiful chest.”

As for Satrapi, the future is bright. At the age of 43 there are plenty more films left in her, and with a desire to explore different genres and ideas, there are really no bounds as to what she can achieve.

She said: “I want to explore everything that is possible because this is the only thing that is exciting - doing the same thing I already know how to do, why do it?

"It is exciting for me, this fear of ‘oh my god am I going to do that?’ It’s what gives me the energy to move forward and want to do things.”