Kristen Stewart is "gung-ho" in her new movie role.

The actress stars in the Rupert Sanders-directed fantasy film Snow White and the Huntsman. Kristen was dedicated to delivering her own stunts in the high-octane role, leaving Rupert suitably impressed.

"Kristen is a very driven, visceral, intuitive actress. From a director's point of view, it's great to get into her headspace," he explained in an interview with MTV News.

"We did a lot of work together on the script and character, and she really helped inform me how that character was feeling, which really helped my process getting the character onscreen. Kristen was doing a lot of her stunt work, she was riding horses, she was jumping from high precipices into freezing cold water, she was fighting dwarves she's gung-ho."

Kristen's co-star Charlize Theron also impressed with her attitude. Rupert says the star - who plays evil queen Ravenna became immersed in her role.

"[She] becomes fiendish," he said of Charlize.

"She was willing to get in tubs of black oil, surrounded by dead ravens, and crawl her way out. For a director, what's great about these two actors is that they will go beyond what you ask of them, and I think it really shows in the performances they've given. They're both very unlike any performance I've seen either of them deliver."