Bullock is capping a long list of actresses who had been considered for the role. Angelina Jolie was up first but the studio balked at her $20 million fee. Next for consideration were Marion Cotillard, Scarlett Johansson and Blake Lively; Portman was in serious talks to take the role but had to back out after her schedule got crowded.
Scripted by Cuaron and his son, Jonas, the film will begin shooting in the UK in January.
This will be Bullock's first outing since 'The Blind Side.' The Oscar-winning actress has been considering several projects at this point in time, including 'Extremely Loud and Incredibly Close' with Tom Hanks.
Get more on Sandra Bullock at PopEater