WATCH: Even Britney Spears Gets Starstruck! Ed O'Neill Reveals He Didn't Recognize the Singer When She Asked for Airport Fan Photo

Britney Spears is used to constant attention, but the tables turned when she ran into Ed O'Neill at the airport last spring.

"I was flying alone to Hawaii. I was waiting for my flight to board," the Modern Family star, 70, told his Finding Dory costar Ellen DeGeneres Monday on her talk show.

"They told me the flight was boarding, and I picked up … a little Modern Family hat. I saw a woman approaching me, so I just flopped it on, you know, I was leaving. She came up and said, 'Oh, Mr. O'Neill, I love Modern Family, and you're my favorite on the show.' And I was like, 'Well, I'm here, and I'm the only one here.'"

Sure enough, the Married… with Children vet didn't recognize the 34-year-old pop icon, who asked him for a photo, which eventually got 6,600 (and counting) likes after she tweeted it on March 21, captioning the shot: "Fancy running into this guy! Such a sweetheart!!"

And as it turns out, even the Billboard Music Awards' latest Icon Award recipient still gets star-struck, too.

"'Could you please … and I know you're in a hurry…'" O'Neill recalled of Spears' fan-girl photo request.

"So I said, 'Sure, fine, you know, okay.' So she sat there, and we took it, and I said, 'Have a nice trip. I'm going,'" and I left. So the next day, my manager texts me and goes, 'What is this? 53,000 likes. It's Britney Spears.'"

As shocked as The Ellen DeGeneres Show host was surprised to hear O'Neill didn't identify the singer, the actor maintained his ignorance.

"I mean, look at my face: Do I look like I'm sitting with Britney Spears?" O'Neill joked. "You know, my daughter, Sophia, she said, 'You are a moron.'"