All it took for Tessa Thompson to transform into Marvel's mythological warrior woman Valkyrie was playful fierceness ... and lots and lots of sword training.

Fans attending the Marvel Studios panel at San Diego's Comic-Con International got their first look at just how fierce the Asgardian could be when she delivers a familiar captured Thunder God to the Grandmaster in a preview of "Thor: Ragnarok," and Thompson couldn't have been more pleased with the emotional response.

The actress, best known for her performances in "Westworld," shared a few insights backstage with Moviefone, including shifting the character from her decidedly Nordic look from the comics to a more diverse big screen incarnation and the equally physical key that helped her embody the spirit of the role.

Moviefone: It must have been amazing to be in that room and get the love blasted back from everybody.

Tess Thompson: Oh, my goodness, yeah, it is! It's hard: you can sort of see the first five rows of folks, and beyond that, you just sort of feel, energetically, a lot of people that are very, very excited. There was one woman in particular that was kind of just weeping openly, our whole panel. I think she was a very big Tom Hiddleston enthusiast and a Loki enthusiast.

But in general, I think the joy of working on these films as an actor is to play in a space of such imagination. So it's so fun to come to a place where people, that's what they do, they're investing three days of seeing the things that make their imagination light up, and that's so fun to be around.

Tell me about this character as she's existed in the comics, historically, and then the version that you get to play in the movie, and the mix of those two.

Yeah, Valkyrie pops up in different places -- she hangs out with the Defenders -- but what was so exciting, I think, in the context of our film is that Marvel really gave [director] Taika [Waititi] a lot of creative freedom with imagining these characters anew. Which is not to say they're complete departures from the source material, but we see a new Bruce Banner, we see a new Hulk, we see a new Thor. We see these characters evolve and change, and the same is true of Valkyrie.

I think they wanted to make a Valkyrie that felt current, and they wanted to respond to a lack of representation in these films, frankly. I think they also just wanted to find someone that could imbue her with a sense of wit and fun and play and fierceness. So it didn't matter so much what she looked like, and I'm just lucky that she ended up looking like me.

Did the wardrobe get you halfway there?

Yeah. [Laughs] Also, learning how to work with swords. I worked with a fantastic swords master named Ruda [Vrba], who trained Gal Gadot. So just really embodying that and working on the training -- I think that's one of the great joys of working on these films, as many of the actors have said, is just the physical challenge of it that you don't get to do really anywhere else in the same way.

And if you ever need to pick up a sword in real life, you know how to use it.

Yeah, true! I know. It might be hard to get through TSA, but we'll see.