Zoe Kazan makes Ruby Sparks fly with boyfriend Paul Dano

Actress Zoe Kazan not only stars in the romantic comedy Ruby Sparks, she also wrote it – and she didn’t have to look far to cast the other lead.

The film is about a writer called Calvin (Paul Dano) who creates the character of a girl who then comes to life.

Kazan explained: "At first I was very concentrated on these characters, who they were, they were speaking so clearly to me.

“Then Paul, who plays the main character in the movie, he's also my boyfriend. He read the first 10 pages said: 'Are you writing this for the two of us?'

“As soon as he said it the idea really grabbed me.”

The real-life couple co-star in the film directed by Little Miss Sunshine's husband and wife team Jonathan Dayton and Valerie Faris. Annette Bening and Antonio Banderas co-star as Calvin's eccentric parents.

They loved the idea of working again with Dano, who starred in Little Miss Sunshine, and were intrigued by Kazan's script. Dayton said: "I loved that it was really about something, that you had this fantastic premise, but ultimately it was about how we all desire to control the person we're with. There was a lot to explore.”

For Dano, acting alongside his real life love and teaming up with Faris and Dayton again was "a joy".

"The four of us care about it so much, and we had a great trust in each other,” he explained. “Everybody is kind of putting themselves out there and so you get really close because you always feel vulnerable too.

“I would say it's about as good as it gets."

  • Ruby Sparks opens in the UK this Friday.