Zawe Ashton reveals the Marvel villain advice she received from fiancé Tom Hiddleston

Zawe Ashton got some firsthand Marvel insight when she signed on to play the villain in The Marvels.

Known for films like Velvet Buzzsaw and Mr. Malcolm's List, the British actress is joining the Marvel Cinematic Universe as Kree revolutionary Dar-Benn, facing off against Brie Larson, Teyonah Parris, and Iman Vellani. In EW's new cover story on The Marvels, Ashton explains that she had long hoped to work with director Nia DaCosta and jumped at the chance to suit up as a supervillain.

While preparing for the role, Ashton got some advice from another Marvel villain: her fiancé Tom Hiddleston, who's played trickster god Loki since 2011.

"It led to some incredible conversations about his experience being part of this franchise for over a decade," Ashton, 38, tells EW in an interview conducted prior to the start of the SAG-AFTRA strike. "One of the main takeaways from our conversations was: 'What you put into Marvel, you get back.' He said, 'If you go into this with an open heart and a great work ethic and just want to provide an amazing experience for the fans, you'll have an amazing experience on those sets.' He really empowered me in that way."

Jeff Spicer/Getty Images Tom Hiddleston and Zawe Ashton

Ashton says she and Hiddleston often try to keep their work lives separate, but she remembers one particularly fun day when he helped her rehearse a Marvels scene. Afterward, they looked under their kitchen table to see their confused dog, wondering why two terrifying Marvel villains were loudly running lines above him.

Plus, Ashton adds, Hiddleston had some additional pointers for when she got to set.

"He also had some very good practical advice, which was: Make sure you have enough zippers to go to the bathroom in your costume," she says with a laugh. "Which is very good advice, I realize now."

Marvel Studios Zawe Ashton as Dar-Benn in 'The Marvels'

Ashton stars in The Marvels as Dar-Benn, a Kree leader fighting to restore her home after a lengthy civil war. (It's a new, expanded take on the character, who has a minor role in the comics and was originally written as a man.) Ashton trained for weeks, learning to properly wield Dar-Benn's imposing war hammer, and in the film, she clashes with Larson's Captain Marvel, Parris' Monica Rambeau, and Vellani's Ms. Marvel.

"It's this all-female sci-fi extravaganza, with a woman on the other side of the camera," Ashton adds. "I felt very moved, actually, being involved in it. It's not an environment you're often in — a huge-budget movie with all these badass women and Samuel L. Jackson. That just doesn't happen."

The Marvels hits theaters Nov. 10. For more, read EW's full cover story on the film.

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• How Ms. Marvel star Iman Vellani went from fangirl to superhero

• Tom Hiddleston and Zawe Ashton are engaged