To be clear, O'Neill knew there was an international pop star named Britney. But he was unaware that Ms. Spears was the fan with whom he recently posed for a picture. As the actor explained on The Ellen DeGeneres Show, "I saw a woman approach me [in the airport], and she came over and she said, 'Oh, Mr. O'Neill, I love Modern Family. You're my favorite on the show.' And I thought, well I'm the one here."

So when this mystery fan, who "couldn't have been nicer," asked to take a photo with O'Neill, he obliged. It wasn't until his manager called about a picture getting a ton of likes on social media that O'Neill found out he had posed for a picture with Britney Spears. At least now she'll know he wasn't just being nice because she's famous! Check out O'Neill's interview with Ellen, below.