Nicola Yoon, the author of the young adult novel Everything, Everything which has been adapted into a feature film, said she cried her eyes out when she first visited the set of the film.
The debut novel from the writer topped the New York Times bestseller list and was subsequently adapted for the big screen by Warner Bros. with actors Amandla Stenberg and Nick Robinson in the leading roles, and Yoon revealed that her first day on set was incredibly emotional for her.
Yoon, who grew up in Jamaica and New York, said that she wrote the main character Maddie to look like her young daughter Penny, as "everyone should see themselves as the hero of a story".
During her first set visit to the film along with her husband and daughter, Yoon revealed that Penny was excited to see actress Amandla Stenberg as "she looks just like me".
Speaking to RTÉ Entertainment in London, Yoon said: "The first time Penny, my little girl, met Amandla she said 'Oh momma, she looks just like me'.
"It was one of those moments where you do a thing, and you plan it, and then it happens. It's very rare that the thing you plan goes exactly how you planned it, but it did and it was very emotional for us."
The best-selling writer was full of praise for Stenberg and Robinson's portrayal of her much-loved characters, saying "they have such good chemistry with each other".
"When I first was at the set they were doing an airplane scene, and I just cried my eyes out", she said of witnessing her characters coming to life. "The first time I saw it I just thought 'This is insanity'.
"My little girl was worried about me, she was like 'Why is Momma crying?' and my husband was like 'It's tears of joy, she's actually really happy'. And now my daughter says that sometimes too if she's crying 'It's tears of joy momma!'"
Everything, Everything is about teenager Maddie who has severe combined immunodeficiency (SCID) which means she can never leave her hermetically sealed house in Los Angeles, where she lives with her mother. However, when a handsome young man moves into the house next to her, Maddie wants to expand her world, even if it means risking her life.
Yoon added that it was "one of the craziest, most surreal moments" to see the world she had created in the book realised on the set, joking: "Did you get into my head, how did you do that?! It was incredible."
#WeNeedDiverseBooks because this is my family pic.twitter.com/lepPAiSWHh
— Nicola Yoon (@NicolaYoon) May 1, 2014
The popular author also spoke passionately about her support of the We Need Diversity in Books organisation, which originated in 2014 when a photo she tweeted of her family went viral.
"When we talk about diversity we talk about it in these big, political ways, but these are very personal issues", Yoon said.
"The main character of Everything, Everything looks the way she does because my daughter looks like that, and I wanted her to see herself in a book when she grew up because I didn't have that experience very much when I was younger. Everyone should see themselves as the hero of a story."
Everything, Everything is out in cinemas on Friday, August 18.
