Paul Dano didn't kiss his girlfriend for a fortnight leading up to the making of his latest film, Ruby Sparks.
Acting opposite real-life partner Zoe Kazan, the 28-year-old wanted the couple's on-screen interaction to be real, yet fresh.
"Hopefully we were able to bring intimacy and chemistry to it in a way that would have been much harder with somebody I didn't know and didn't love," Dano says.
"We also had to do things ... we didn't kiss for two or three weeks leading up ... just 'cause you have to get that [new] sense."
Not a romantic comedy but rather a fantasy, according to co-director Jonathan Dayton, Ruby Sparks is a roundabout love story between dysfunctional but successful author Calvin (Dano) and the main character in his latest book, Ruby (Kazan) who materialises one morning in his kitchen.
In a subsequently surreal and sometimes dark world, Calvin moulds and shapes Ruby as he develops her character in his typed narrative.
Kazan, 29, set about writing the script with no intention of herself or Dano, her long-term boyfriend, starring in the production.
"It was very early in my writing process that I showed Paul and he asked me if I was writing it for the two of us.
"And when he said that, it seemed really clear that's totally what I was doing, but it took him pointing it out for me to realise," she says.
For Kazan, it presented a perfect opportunity to write into Dano's character something she would like the world to see more of: his smile.
"When you love someone you see the best in them and I wanted other people to see the best in Paul too."
Otherwise Kazan says she is happier acting than writing and was content to hand over her script to directors Dayton and Valerie Faris, who were behind another of Dano's films, Little Miss Sunshine.
What: Ruby Sparks, offbeat American comedy starring Paul Dano and partner Zoe Kazan
When and where: Opens at cinemas on Thursday