Credit: Michael Buckner/WireImage

Now that she's single again, Dianna Agron is in high demand.

Prior to Wednesday's private dinner celebrating NYLON's December/January cover girl, 90210's Trevor Donovan tweeted that he was hoping to take a picture "kissing her on the cheek."

The two stars first met when they shot on an OP ad campaign in early 2010, and given Agron's recent split with Sebastian Stan, the 33-year-old actor saw the NYLON dinner as his opportunity to make a move.

"Trevor spent the night flirting with Dianna, who really didn't seem interested," an onlooker tells Us Weekly. Despite sharing two Blue Moon beers by the bar, Agron steered clear of the six-foot-two actor once dinner was served.

Though Agron, 25, managed to put on a brave face during the event, a source tells Us her ex, 28, is still reeling from their breakup.

"Sebastian is for sure broken up by it. He liked her and definitely tried to make it work the best he could," says the source of the bicoastal stars.

For now, the Captain America: The First Avenger star is doing everything he can to avoid thinking about Agron. "He's got a few things filming, so he's got a lot to keep his mind on."