Sandra Bullock Reveals The Hardest Part Of Being Lost In 'Gravity'

Actress tells MTV News the physical rigors of shooting were trumped by the emotional ones.

It's been nearly 20 years since Sandra Bullock sat behind the steering wheel of a runaway bus in "Speed," but that was transportational child's play compared to the catastrophes the actress faces in Alfonso Cuarón's gripping "Gravity."

The film follows Bullock's Dr. Ryan Stone, a medical engineer on a mission in space alongside George Clooney's astronaut Matt Kowalski. But if you've seen even a minute of the film's trailer, you know things go horribly wrong with their craft, stranding the pair in the heavens. We repeat: They are lost in space.

The shoot was a grueling one for Bullock, though she did admit to MTV News that the physicality involved was actually one of the easier aspects.

"Preparing physically was easier [than preparing emotionally]. It wasn't easy when you were doing it, but you knew what you had to do," she said. "You knew how you had to train to get from A to B, B to C, and also to have your core be strong enough to execute the gymnastics and whatever they wanted you to do. Physically, I wanted her to look a certain way because of the character, and fortunately those two went hand in hand."

Check out photos of Sandra Bullock, George Clooney and more stars on the "Gravity" red carpet!

Though overwhelmingly action-oriented, the film is also something of a character study of Bullock's world-weary Stone, requiring heavy emotional-lifting on the part of the actress.

"Emotionally, you could do all the homework. We had discussions on who she was, who she wasn't, what her loss would be, if we would say things or show things, limit the words, add words. The process never stopped," Bullock explained. "Every day I would stop the technology and go, 'I don't understand where we are. Remind me where we came from.' Because it was so out of sequence and disjointed. So the hard part was every day, in whatever confined space that you were in, trying to find a natural way to act after you were told where to start, where to end, how your fingers were and how many minutes you had to do it, and then you had to do your job."

"Gravity" opens Friday.