English actress Lily James looks good in period films and shows, and this is why she has nabbed lead roles in films such as "Pride and Prejudice and Zombies" and "Cinderella," not to mention the television series "Downton Abbey" and "War and Peace."

"I can't really believe I've played all these literary heroines. It's bizarre to me, with Liz Bennet and Natasha Rostov, and I'm going to do Juliet in 'Romeo and Juliet.' It's very daunting," James shared during an interview with Collider.

For James, each role has its own challenges. However, she considers the series "War and Peace" as the most difficult thing she's ever done.

"'Downton' was my first big thing, so that was daunting, and it was a show I'd already loved. Cinderella was Cinderella. I was terrified. I didn't want to let anyone down. The whole world knows that character and loves that character," she said. "And Natasha was daunting because it's probably the greatest acting challenge I've had so far. It starts off when she's young, youthful, open and spirited, which are qualities that I've played before in other characters But as the journey goes on, by the last episode, it's a completely different story. That was frightening for me to play such intense scenes."

James credits director Tom Harper for helping her develop the character from youthful innocence to hardened maturity.

"I wanted her to feel really young, at the start. I thought was really important, so that you felt that journey and felt that openness and you understand why she falls for Anatole and how hard she is on herself. There are such depths to her despair versus that joy, at the start," she said.

The actress admitted that she has never read the novel "War and Peace" prior to landing the role of Natasha, but once she started reading Leo Tolstoy's work, she found it difficult to stop.

"It was a complete page-turner. You get so besotted with the characters and into the families, and you want to know who's going to end up with who and who's going to die and what that's going to mean," she said. "Natasha's journey is so vast. She becomes a woman, and she changes, grows and discovers. It's just the most beautiful story."

Even Kenneth Branagh, who directed Cinderella, cannot help but gush about Tolstoy's work. "It will be one of the great joys of your life to read it," he told James.