The `Lost in Translation` actress and the `Gossip Girl` beauty are both vying for the main female part in sci-fi movie `Gravity`, which tells the tale of a female astronaut who gets lost in space.

It had been thought Scarlett had "verbally agreed" to star opposite her `Iron Man 2` co-star Robert Downey Jr. but Blake is now being considered for the part.

The film - which is being directed by Alfonso Cuaron - is being dubbed a contemporary survival thriller, and will be at least 60 per cent CGI (computer-generated imagery). It will also feature an ambitious opening 20-minute sequence.

As well as `Gravity`, it was recently revealed Scarlett is being lined up to play Vince Vaughn`s lover in a new film.

The 25-year-old actress is reportedly in talks to appear in `Old St. Louis` as a secretary who is secretly romancing a travelling salesman.

In the comedy drama, Vince`s divorced businessman character tries to combine his latest cross-country work trip with an attempt to reconcile with the teenage daughter he rarely sees.

However, it is thought Scarlett won?t be able to do both films, as they are slated to begin production in October.
sections: Celebrities