Blake Lively and Scarlett Johansson vying for Alfonso Cuaron’s Gravity… Blake Lively and Scarlett Johansson are the frontrunners for the lead role in director Alfonso Cuaron’s Gravity. According to reports both Johansson and Lively have tested for the role of a female astronaut lost in space and a decision is expected to be made within the next week or two. In the film, co-written by Alfonso and his brother Jonas, astronauts repairing the Hubble telescope are hit with an avalanche of satellite junk. The surviving astronaut must fight her way back to Earth, where she hopes to reunite with her daughter. Robert Downey Jr also stars in the picture.