The 'In Time' actress - who has previously dated Ryan Phillippe and Dominic Cooper - has split from New York based real estate executive Andrew Joblon after four months of dating.
A source told Life & Style: "They're definitely over. He celebrated New Year's Eve in Aspen and she wasn't there!"
"[The split] happened gradually over time. They still talk. They aren't what they were, but they still hang out and are on great terms."
Amanda, 26, began dating Andrew, 28, a few months after she split from 'Lincoln Lawyer' star Ryan, 37.
Amanda recently starred in 'In Time' with Justin Timberlake and admitted she had a crush on her co-star, who has since gone on to propose to Jessica Biel.
She previously said: "Oh yeah of course I fancy Justin, I've known him for a while, he's awesome.
"In the movie our characters have this instant connection. They immediately flirt and it's awesome but then he takes her hostage because that's the only way he sees to get out of this situation he's in. And then she's confused and their dynamic changes and it's sexy and great."