natalie230.jpgNatalie Portman is going from tormented ballerina in Black Swan ... to being trapped in space for the upcoming drama Gravity.

Portman, who landed the role after Angelina Jolie reportedly dropped out, will play opposite Robert Downey Jr. The movie focuses around Portman's character who gets stranded on a space station after floating debris crashes into it ... wiping out everyone. Her goal is to get back to Earth where her daughter will be waiting for her return. Downey's exact character hasn't been revealed, however it is said to be just a supporting role.

The space-themed movie will be shot in 3D ... and has a price tag of $80 million!

Other actresses like Scarlett Johannson and Blake Lively were being considered for Portman's role, but she ultimately landed it. Producers are said to be happy with their choice especially because Portman's movie salary comes in at nearly half of Jolie's.

Gravity will start shooting in January. Talk about out-of-this-world casting!