Emilia Clarke, Sam Claflin pair up in Me Before You, film of ex-Hong Kong reporter’s hit novel

To fans of HBO’s Game of Thrones, Emilia Clarke is Daenerys Targaryen, a shrewd, dragon-wielding conqueror and one of TV’s fiercest heroines.

So when Me Before You director Thea Sharrock suggested she play Louisa Clark – a spunky, idealistic young woman who takes a job caring for a wealthy, wheelchair-bound quadriplegic (Sam Claflin) – screenwriter Jojo Moyes was understandably puzzled.

“I couldn’t see it,” says Moyes, who adapted her 2012 romantic novel for the big screen. “She was, for me, irrevocably linked to long, blonde hair and dragons and looking very stern. But the moment you actually see her without the [Thrones] wig, she’s so warm and bubbly, and actually has the physical look of Louisa. It really took no time at all.”

Playing someone who shares her optimistic outlook and humour was part of the appeal to Clarke, who calls Louisa (nicknamed “Lou”) a “more innocent version” of herself.

Reading the book for the first time, “I was in love by page 3,” says Clarke, 29, teasing and laughing with her Me Before You co-star throughout an arduous day of interviews. “Lou felt like such a perfect extension of me. I just understood her, and it was that understanding that brought my excitement.”

Lou’s unbridled joy is a stark contrast to her embittered love interest, Will Traynor. The jet-setting banker has a glamorous girlfriend (Vanessa Kirby) and passion for extreme sports, until he is struck by a motorcycle and paralysed from the neck down. When Will’s mother (Janet McTeer) hires Lou – who is supporting her working-class family – he initially goes out of his way to put her down, and the two butt heads.

At first, “he’s depressed and angry at the world, but she enters his life and isn’t afraid of the wheelchair and his quadriplegia”, says Clafin, 29, who moviegoers know best as Finnick Odair in the Hunger Games series. “He needs someone to be honest and truthful and put him in his place. Everyone’s obviously just been skirting around him and not treating him like a human, and she’s a breath of fresh air. She’s different from anyone he’s ever met.”

As their friendship grows, Lou learns that Will has decided to end his own life with assisted suicide. In a last-ditch attempt to remind him why life is worth living, she plans a series of “bucket list” excursions to a horse racetrack, opera and beach paradise, where an unexpected romance blossoms.

For Claflin, the emotional challenge far outweighed the physical ones of losing weight and making his body appear limp. “I had to kind of come to terms with why would he make this [decision],” he says. “The answer is that he’s a very determined young man and will do anything in his power to give the people around him the best. In his mind, it’s a very selfless act.”

Moyes adds: “The film asks you to think, ‘Well, what would I do if I was in the same position?’ … Anything that encourages us to think a little more and judge a little less has only got to be a good thing.”

Me Before You opens on July 14