Tessa Thompson on Revolutionizing the Marvel Universe and Her Dream 'Thor: Ragnarok' Spinoff (Exclusive)

Tessa Thompson doesn't yet know she is the standout star of Thor: Ragnarok. In Marvel's latest release, Thompson plays Valkyrie, a disillusioned Asgardian warrior-turned-galactic bounty hunter who bands together with the God of Thunder to save the universe. Think of her as the Han Solo of the MCU: a prickly antihero, a swaggering space bandit with a tragic backstory and penchant for quippy one-liners and booze. And though the actress has been consistently singled out by critics -- "The Marvel universe needs to see more of her. She's a star," one review declares, while others call her "wonderfully rambunctious" and "so damn cool" -- on the red carpet at the Ragnarok premiere, Thompson hasn't yet actually seen the movie.

"I wanted to wait and see it with them first," Thompson tells ET, referring to her plus-eight for the evening: Her dad and mom, her two sisters, her younger brother and her three best friends. (Many of whom had never attended a premiere before.) "I grew up a stone's throw from here and I would walk these streets and look at these stars. So, it feels like a full circle moment!"

Thompson made her debut as an actress onstage in a L.A. Women's Shakespeare Company production of The Tempest at the age of 19. Now 34, she's had success on the big screen, in the award-winning Creed and Selma, and the small screen, on the Emmy-nominated HBO series, Westworld. Considering those credits alone, it's no wonder director Taika Waititi knew she had what it took to play Valkyrie: She's a bit Shakespearian, a bit sci-fi, and packs plenty of moxie.

Oh, and then there's the sandwich. "I ate a sandwich during one of my scenes," she recalls of her audition. "I don't know if a turkey sandwich got me the job, but if it did, I'm grateful!"

One thing Thompson is not, as was noisily gassed about by the corner of the internet where fanboy culture intersects with racism, is white, as the character, based on the Brünnhilde of Norse mythology, is drawn in the comics. "There are plenty of women that look like Valkyrie," Thompson, who is of Afro-Panamanian, Mexican and European descent, allows with a shrug. Her interest, she explains, is in making films that reflect the world we live in. "There are plenty of women that look like me. What was more important for Taika -- and for Marvel in general -- was that they found someone that captured the spirit of Valkyrie. In this case, she happens to look like me."

Once she booked the role, Thompson challenged herself to not only uphold the essence of Valkyrie, but develop the physicality of a sword-brandishing, beer-guzzling badass. "There was very little I could do about my height," she jokes, but she did start training long before arriving on the Australian set ("When I was making Annihilation, in between takes, I had this practice sword which I would lose a lot," she remembers) and during the shoot, tried to follow Chris Hemsworth's diet and would schedule gym visits while he was working out with his trainer. ("They make a lot of grunting noises. That is half of what their workout is. It's just, 'Grrr!'") "Valkyrie, in the comics, is arguably as strong or stronger than Thor," she proudly reveals of gaining 15 pounds of muscle.

"I have never done that much action or stunt work or been in a harness or had a flying horse or been on a spaceship. All of those things that you're like, I don't know what do you do!," Thompson reflected during a recent sit-down during the film's press junket. Yet, the most difficult aspect of playing a superhero might come as a surprise: the cape.

"I know that sounds like-- not a champagne problem, but like a weird superhero problem that we don't think about," she said. "You just trip on them and then the wind machine gets going and it smacks you in the face. So, it felt like a quick boot camp in superhero-ness." It does eventually become normal, though. "We all stand around with half of our costume off and weird suspenders...We have conversations about navigating the demands of superheroes," she added with a laugh. "[And] the sometimes adventurous positions you have to get yourself in to be able to, you know, pee in between takes."

It's not only film critics that have already taken to Thompson's portrayal of Valkyrie. Thor: Ragnarok will not arrive in theaters until Nov. 3, but Valkyrie's face has been plastered on T-shirts and posters and she's gotten her very own action figures, dolls of varying likeness and adorableness. "One mother just wrote me a couple days ago saying that she gave one of those dolls, my doll, to her daughter," Thompson tells us. "And her daughter looked at it and said, 'Me.'"

Thompson has long been an outspoken activist -- or, according to her Twitter bio, "Female Agitator" -- and when she was named Woman of the Year during this year's Elle Women in Hollywood Awards, she said in her speech, "Within [Hollywood], I think we see, yes, that systemic sexism reigns supreme, and I think we also see that systemic racism and discrimination exists." Valkyrie enters the zeitgeist at a time when there is a call for greater diversity, both in the Marvel universe and the industry at large, and better roles for women, opportunities for people of color, and queer representation, all of which are boxes Valkyrie ticks off. ("She's bi," Thompson tweeted. "And yes, she cares very little about what men think of her. "What a joy to play!")

As such, in addition to a rumored role in the upcoming Avengers: Infinity War, out April 25, 2018, Thompson hopes to expand her presence in the MCU to include a crossover with the cast of Black Panther, Marvel's first solo film fronted by a black superhero. "The worlds are colliding more and more," she says of working with friends like Chadwick Boseman and Michael B. Jordan, whom she co-starred with in Creed. "I think we're constantly going to just pitch to Marvel how to get all of the characters in one movie and see what happens."

Thompson has another idea that she's already pitched to Marvel Studios head Kevin Feige, for an all-female superhero hero team-up that would pull together the ladies of the Marvel universe for an Avengers-like assemblage. "I'm really into Valkyrie when she's a part of The Fearless Defenders," she reveals, referencing a run of comic books in which Valkyrie teamed up with the likes of Misty Knight and Warrior Woman. "I think it would be fantastic to have an all-star female team which includes Brie Larson," she suggests, as well as Black Panther stars Angela Bassett and Danai Gurira. "Let's get Tilda Swinton. Lupita [Nyong'o] is in there. Just a really badass group of women."