Bullock is rumoured to be dating Johansson's estranged husband Ryan Reynolds after the pair were spotted enjoying each other's company on New Year's Eve.
The two women came face-to-face at the CAA party at Sunset Tower in Hollywood, and according to an onlooker, 'Sandra hugged Scarlett.'
The source told Us Weekly, 'At first, it looked like they didn't know what to say, but by the end, they were both smiling.
'Sandra had her arm on Scarlett's shoulder.'
A rep for Johansson confirmed, 'They sat with each other.'