The expression New Jersey first lady Mary Pat Christie's face during Donald Trump's victory speech on Tuesday has social media buzzing. But over what, exactly?

Gov. Chris Christie stood to one side of Trump, and New Jersey's first lady on the other, as Trump claimed victory in the Pennsylvania, Maryland, Connecticut, Delaware and Rhode Island Republican presidential primaries. He began to speak about Democratic frontrunner Hillary Clinton during the speech, aired live on several networks and news channels.

"If Hillary Clinton were a man, I don't think she'd get 5 percent of the vote," Trump said. "The only thing she's got going is the woman's card, and the beautiful thing is — women don't like her. And look how well I did with women tonight, OK?"

Mary Pat Christie, who had been looking straight ahead, turned her head and eyes from one side to the other as Trump mentioned the "women's card" — drawing immediate and wide online reaction.

But was there anything to it? Did her reaction have anything to do with what Trump was saying? Was she just looking around the room? Getting antsy after a long day on her feet? That's harder to say.

The governor's expression escaped analysis during the speech despite having a blank stare on his face at times. He got a mention during the speech when Trump called him "fantastic."

During a speech in March in Florida, Chris Christie's thousand-yard stare was the subject of even more attention and ridicule. At a press conference a few days after the incident, Christie said of the "theories" behind the stare: “No, I wasn’t being held hostage. No, I wasn’t sitting up there thinking, ‘Oh, my God, what have I done?'” He said it “wasn’t the kind of circumstance where I’d be jumping up and down, cheering and smiling.”

More reaction on Twitter to Mary Pat Christie's facial expression:

Related video: