Conan O’Brien is 100% Irish, and he’s got the DNA test to prove it.

In a 2019 appearance on The Late Show with Stephen Colbert, O’Brien recalled how he recently took a DNA test, and the results surprised his doctor.

“I’m finding out new things all the time,” O’Brien told Colbert, back in 2019, before telling him of his recent DNA test.

During a routine physical, O’Brien’s doctor offered to run a DNA test for him and called him two weeks later to deliver the results.

“I’ve never, ever, ever had a DNA result like this before,” the doctor told O’Brien, “and I’ve been doing this for ten years.”

O’Brien says the doctor told him “You are 100% Irish.”

“I've never seen a 100 percent anything,” the doctor told O’Brien. “I've been doing this a lot, I've seen 93.5 [percent], I've seen 96.1, I've seen 97. No one is 100 percent Irish.”

The doctor even went on to tell O’Brien that people in Ireland aren’t even 100% Irish.

“The Lucky Charms leprechaun - true fact! - 11% Spanish,” joked O’Brien.

When he asked the doctor what the results could mean, the doctor replied: “What does it mean? It means you’re inbred.”

Watch Conan O'Brien on The Late Show with Stephen Colbert here:

Conan Christopher O'Brien was born on April 18, 1963, in Brookline, Massachusetts, to Ruth O'Brien, an attorney, and Thomas O'Brien, a physician. His paternal grandparents, William O'Brien and Mary McCallion, were both immigrants from Ireland. William O'Brien hailed from County Cork, while Mary McCallion came from County Donegal.

Growing up, Conan was raised in a devout Catholic household. His parents instilled in him a strong sense of Irish heritage and culture, which influenced his worldview and his sense of humor. In an interview with Irish America Magazine, Conan said, "My parents were very proud of their Irish heritage, and they raised us with a strong sense of our Irish roots. It's something that's always been a big part of my life."

In 2012, he traveled to Ireland to film a special episode of "Conan," where he explored his Irish roots and visited several locations in County Cork and County Donegal.

* Originally published in 2019, updated in April 2023.