After Natalie Portman passed on the starring role in his outer-space thriller, Alfonso Cuaron appears to have finally found a leading lady for Gravity: Sandra Bullock. Bullock is in negotiations to take on the part of an astronaut opposite Robert Downey Jr. in the film. Everyone from Angelina Jolie to Marion Cotillard to Blake Lively had been connected to the part, but Cuaron had settled on Portman once Jolie was officially out of the picture. However, after Portman turned it down, Bullock was approached immediately. While the Oscar winner is also in talks to star in Extremely Loud and Incredibly Close, it now looks like this space odyssey will be her first post–Blind Side project to hit theaters. [HR]