Natalie Portman has pushed herself away from Gravity, leaving Warner Bros. to offer the role to Sandra Bullock.

Alfonso Cuaron's sci-fi movie, co-written with his son Jonas, is now turning into the Longest Pre-production Movie Ever. And that's mostly due to problems with its lead female part. First Angelina Jolie was in it, then Natalie Portman was orbiting the role, and now the Black Swan star has jumped out the airlock completely.

Offered the part without a screen test, Portman was the Children of Men director's confident choice to give the project some pull. But now she's passed, Alfonso is lucky to have Sandra Bullock waiting in the emergency pod.

The Blind Side actress, who got awards and box office success, would be a strong bet for Warner Bros., who need a solid return on a film that revolves around a single astronaut for most of the film. Robert Downey Jr. is on board as well, but he's a miniature second fiddle compared to the lead female character, who gets stranded on a space station when debris kills off the rest of the crew.

Which explains why within hours of Portman's rejection, they've already offered Bullock the role. Cuaron might pull this baby into dock yet.