Disney's "Cinderella," opening this week, is a sumptuous period fantasy, full of dazzling costumes, eye-popping sets, and at one genuinely revelatory performance in the form of Lily James, who plays the title character, going from being a sooty nobody to, thanks to some magic slippers, the most sought-after maiden in the entire kingdom.

James's performance is subtle but dynamic. She's able to craft a character whose strength comes from within, whose life isn't dictated by her wicked stepmother (played, gloriously, by Cate Blanchett) or the Prince himself (Richard Madden from "Game of Thrones"). She's determined and self-sufficient even before her Fairy Godmother (Helena Bonham Carter) grants her one magical night out.

We got a chance to speak to James about how she was able to make the character her own, how she initially wanted to play one of the wicked stepsisters, what it was like working with Cate and director Kenneth Branagh, and what her role in the blood-soaked "Pride and Prejudice and Zombies" looks like.

Moviefone: Were you involved with the Mark Romanek version?

Lily James: No, I came onboard the Branagh version. And, actually, I originally auditioned for one of the sisters.

Oh, so you didn't think playing Cinderella was even a possibility?

Well, I don't know. I got the call for the sister and I was actually really excited to play that part. I love playing the quirky or funny or offbeat characters where you don't have to think about being pretty or nice and I was like, "Yay!" And then when I was there, the casting director was there and since I had blonde hair for "Downton Abbey," and she said, "Oh, why don't you read for Cinderella while you're here?"

Did you always want to do a fairy tale?

I loved fairy tales growing up. So I had my dress-up costume with the little plastic royal slippers and thankfully I had two brothers who stopped me from being too princess-y. Belle was always my favorite. I loved her spirit of adventure. And, I think that, as the Disney princesses have progressed over the years, they've become really wonderful, spirited girls, and I liked that.

Was there any particular spin you wanted to put on the character to make her your own?

Well, I felt like they had already done it. When I read the script I was really moved and I was really taken aback by the fact that it was such a classical retelling but there were these differences that made it feel more modern and more relevant. I love that, in this version, Ella isn't waiting around for the prince to save her. She's a much stronger character. That was my spin. If I wanted to do anything with the part, it was that I wanted her to be a strong heroine and to be in charge of her own destiny.

Do you think that your Cinderella is a feminist?

I don't know -- what is a feminist? That would be a big, big answer. Do you think she's a feminist?

She's certainly empowered and never lets any man dictate her emotional state or agency.

Yeah, I agree. I feel like she, even at the end when the Prince comes to rescue her, she says, "This is who I am. I'm this girl. I have no dowry and I'm not a princess. And if you can love me, then fine. And if not, then that's okay too." She's still in charge of her destiny, even in that moment. What's amazing with what Ken has done is that the sequence still feels really romantic. I think she's empowered and I think she rescues the Prince as much as he rescues her.

Can you talk about what it was like working with Cate?

Oh, just amazing. She's an inspiration to me. I can't even begin to tell you how exhilarating it was to work with her. Her stepmother is so rich and full and when I looked at her, it was so interesting to see what she did with her character and I think that, even though it's a fairy tale, it was all a part of making her feel real and deep and multi-dimensional. She kind of forces you into the moment because she's so bloody brilliant.

And what about Kenneth Branagh? I assume he's someone every actor wants to work with.

Oh, yes. It completely excelled all of my expectations. He's so kind and generous and he takes so much time with you and he's got such a big heart. So to be directed by him is rewarding and so refreshing as an actor to completely trust your director. It was the best experience I've ever had acting.

You're doing "Romeo and Juliet" with Richard for Branagh on stage next year, right?

Yes! I'm so excited! When all of this stuff is finished, it'll be sometime next year before we start on the play, so I'll miss him and I'll be ready to work with him again.

The costumes in this movie are incredible, but obviously everyone is curious about were the glass slippers like? Were you actually wearing anything?

Well, the slippers were made of Swarovski crystal and they were so beautiful and valuable that there was not a chance in hell that I could actually wear them. So they were CGI'd in, onto my foot. I know that's not very magical, but since I didn't actually wear the slipper, we can say that Prince Charming is still out there searching for his Cinderella!

What if there's a Lily James version of Cinderella that gets introduced into the theme parks?

I don't know. The good thing is that even though I've worn this dress and stuff I already feel like it doesn't feel like the character belongs to me. The character feels quite separate already. So, in some ways, I think like it'd be version of me walking around, which would be really weird.

What can we expect from "Pride and Prejudice and Zombies"?

I don't know. I filmed it already and it was a really weird, wild, wonderful time. I have no idea what it's going to be like. But what was really cool about it was it was such a different character from Cinderella. With Cinderella, all her strength came from within, but with Elizabeth Bennett, in our version, she's a zombie slaying warrior. So I got to use all my strength, physically, so it was cool to get to do that right after Cinderella.

Would you like to do a full-on action movie?

I never thought I would say this, but I'm desperate to do an action film. I absolutely loved it.

"Cinderella" casts its spell in theaters March 13.