Credit: Splash News Online

New year, new romance for Sandra Bullock and Ryan Reynolds?

Fresh off highly publicized, messy divorces, the sexy Proposal costars were spotted "partying the night away" together on New Year's Eve at Bess Bistro (which Bullock owns) in Austin, Tex., a witness tells the new Us Weekly, out now.

"They were very playful," the onlooker says of Bullock, 46, and Reynolds, 34, who were "smiling the whole time and occasionally touching...What a hot -- and quick -- rebound for both of them!"

Indeed, as first reported by Us Weekly, Reynolds and Scarlett Johannson ended their marriage in early December after just two years together; Bullock has reportedly been single since her devastating June divorce from Jesse James following a shocking cheating scandal.

"I'm sure they've bonded over the breakups," a Reynolds insider tells Us. "Going through a divorce is a unique thing to live through."

And while Bullock's rep tells Us that the duo are "nothing except good friends," Reynolds' pal adds that the "chemistry" between the pair was obvious on the 2009 set of The Proposal.

"Ryan always got excited talking about Sandra and liked being around her," the source says.

For much more on Bullock and Reynolds' "amazing" New Year's Eve, their special friendship, how she's the "perfect person" for him to lean on post-split, and how Bullock remains close with Johansson! -- pick up the new Us Weekly, out today!