The internet’s latest obsession occurred at, of all places, a Coldplay concert in Foxborough, Mass.

During the concert on Wednesday night, Chris Martin, the band’s frontman, announced that he would be singing to a select few fans in the crowd. “The way we’re going to do that is using our cameras,” he said. “So, if you look at the screens, we’re going to come looking and see who’s out there to say hello to.”

After Mr. Martin sang a happy birthday song to one ecstatic fan while playing mellow guitar, a giant screen in the stadium showed a couple embracing. The man, who the internet quickly identified as Andy Byron, the married chief executive of a tech company called Astronomer, held his arms around Kristin Cabot, the company’s chief people officer who is not his wife.

“Oh, look at these two,” Mr. Martin said, prepared to sing another sweet song. Then things became awkward.

When Ms. Cabot noticed her face on the screen, she immediately jumped out of Mr. Byron’s arms, covered her face and turned around. He ducked out of view. A woman standing beside them was seen cupping her face in disbelief, her mouth wide open.

Mr. Martin, realizing what was happening, said: “Wow, what? Either they’re having an affair, or they’re just very shy. I’m not quite sure what to do.”