Sandra Bullock negotiating for 'Gravity' role

Sandra Bullock has entered talks to star in Alfonso Cuaron's space drama Gravity.

Warner Bros had initially offered Natalie Portman the lead role, but the Black Swan actress was forced to decline when she could not find time to fit it into her schedule.

Cuaron has experienced a protracted search for a star, initially getting turned down by Angelina Jolie. Actresses such as Rachel Weisz, Carey Mulligan, Scarlett Johansson and Blake Lively have also been considered.

The film centres on two astronauts trying to survive on a remote space station after the rest of their crew is wiped out by space debris. Like Cast Away, large portions of the story will reportedly feature just one character on screen.

Robert Downey Jr. is still attached to star as the surviving male astronaut.

Gravity, which will be produced by Harry Potter's David Heyman, is due to begin production next year.