The Chase host Anne Hegerty was shocked to discover she is related to the Queen.
The quiz master appeared on genealogy series DNA Journey and learned that Her Majesty is her 19th cousin, reports the Sun.
Hegerty, 63, confessed she'd heard it before from her grandmother but didn't believe it.
"Wow, that is cool. But my grandmother was the most tremendous liar," she said.
"My aunt said she was a romancer and she'd embroider life a bit, so I always felt that anything from my grandmother had to be taken with a pinch of salt."
Through her mother, Hegerty is related to the Hayes family - one of whom married Robert the Bruce's daughter Princess Elizabeth in 1370.
This links her to the present royal family, making the Queen her 19th cousin.
The Chaser, who has been on the game show since 2010, added: "My mother was always deeply disapproving of the idea of anyone knowing about their ancestors.
"She'd say, 'it doesn't prove a thing, dear'.
"As a child I was always curious about this stuff and my mother was always very repressive.
"I think it was because on my mother's mother's side there's quite a bit of posh, and my mum thought I'd grow up to be a terrible snob.
"But I've already grown up to be a terrible snob, so really there's nothing to hide."
Hegerty has opened up about her unhappy childhood in the past, partly caused by her autism.
She was finally diagnosed with Asperger's syndrome at the age of 45.
She told the family history show: "I tend to be in a way rather cynical about families.
"People say, 'were you brought up in a nuclear family?' and I was like, 'it kind of exploded, so yeah'.
"My dad left home just before Christmas.
"He left my mother a note saying, 'for Christmas 1970, one house free from husband'."