The 72-year-old actor dropped the clue to Ellen DeGeneres on the Monday episode of her show.
“You did 'Married... with Children' for 11 seasons. And then this ['Modern Family’] with 11 seasons. Are you going to do something big on the last season?” Ellen asked O’Neill.
“I think we may go on a trip,” he replied. “We may go to Colombia, where Sofia’s from. Barranquilla or something like that. It sounds something like that.”
As O’Neill struggled to pronounce the name of the city, she joked: “I’m sure it’s not pronounced that way.”
“Close,” he defended himself as the audience laughed. He added: “It’s supposed to be very beautiful.”
O’Neill also told the daytime host he knew Meghan Markle on the set of “Married... with Children,” because the Duchess of Sussex’s father worked the cameras for the TV comedy.
The actor was playing Ellen’s game called “Who’s This?” where he was supposed to name celebrities based on photographs of them -- because O’Neill had admitted he didn’t recognize Britney Spears or Taylor Swift when he met them in person.
When a photograph of Markle showed up during the game, O’Neill recognized her, saying: “Oh, that’s Markle. Right? Oh, my gosh, you tried to fool me.”
After the audience applauded, he said: “By the way, she grew up on the set of ‘Married... with Children.’ Did you know that?”
He went on, “Her father was a camera operator, and she used to come on the set in a little Catholic school uniform. She was, like, 9.”
“You should have gotten to know her more,” Ellen suggested.
The ABC series was an immediate hit after its debut in September 2009. It began a five-year streak of winning the Emmy for best comedy. Actors Ty Burrell, Julie Bowen and Eric Stonestreet each won two Emmys. It's currently seen by nearly 5 million viewers a week.
Fox News’ Jennifer Earl contributed to this report.