Trailer Sneak Peek: Clooney Defies 'Gravity'

This Thursday ET is debuting the first trailer for the highly anticipated Gravity starring George Clooney and Sandra Bullock, and we have a first look at heart-pounding footage from the outer space thriller!

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In theaters October 4, Gravity centers around a pair of astronauts struggling to survive after a disaster in space separates them from their ship. Bullock plays Dr. Ryan Stone, a brilliant medical engineer on her first shuttle mission, with veteran astronaut Matt Kowalsky (Clooney) in command of his last flight before retiring.

On a seemingly routine spacewalk, disaster strikes and the shuttle is destroyed, leaving the astronauts completely alone -- tethered to nothing but each other and spiraling out into the blackness. As fear turns to panic, every gulp of air eats away at what little oxygen is left. Can they figure out a way to make it home alive?

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Directed by Alfonso Cuaron (Harry Potter and the Prisoner of Azkaban, Children of Men), the long-in-development project has seen a variety of A-list talent attached at various points, including Robert Downey Jr., Angelina Jolie, Natalie Portman, Marion Cotillard, Scarlett Johansson and Blake Lively.