Credit: Jeff Vespa/; Steve Granitz/

The most unlikely coupling on Golden Globes night?

Sandra Bullock and Scarlett Johansson! After talking for 15 minutes at the CAA party at Sunset Tower in West Hollywood, "Sandra hugged Scarlett," a fellow reveler tells the new Us Weekly, out now. (The actresses coincidentally wore very similar dresses for the night.)

"At first, it looked like they didn't know what to say, but by the end, they were both smiling," the observer says, adding "Sandra had her arm on Scarlett's shoulder."

The two had been pals, even smooching on stage at the MTV Movie Awards last June, but hadn't seen one another since Johansson ex Ryan Reynolds cozied up to Bullock, 46, on New Year's Eve.

That didn't stop the Iron Man 2 actress, 26, who filed for divorce from Reynolds after two years of marriage Dec. 23, from dining with Bullock earlier that same night.

"They sat with each other," a rep for Johansson tells Us.

Get much more on Sunday's star-studded Golden Globes -- all the parties, all the dresses, all the encounters --- in this week's Us Weekly, out now!