Gloria Hunniford is shown receiving the surprise news that she is a cousin of Tom Allen in this week's DNA Journey.
The ITV genealogy show follows comedians and friends Allen and Joel Dommett in Thursday's episode, where they discover more about their ancestors and relatives.
For TV host Allen, there is a shock revelation when he is introduced to his long-lost cousin – veteran of TV presenting, Hunniford.
Allen is shown laughing that Hunniford, 82, is "disappointed" to find that he is part of her family and not Dommett as she arrives to meet her surprise relation.
The Cooking with the Stars host was shown looking anxious as he awaited the arrival of the mystery celebrity.
He said: "I'm so nervous. It's really intimidating, the whole thing. What if they're like, slightly irritated by me.
"It's exciting, but...I can't rest."
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Allen looked thrilled as a shocked Hunniford arrived in the room.
She said: "Oh my goodness! I love both of you," as she waited to find out whether she was related to Allen or Dommett.
As Allen told her they were cousins, she said: "Is it you? Oh, it's you Tom," while looking over at Dommett.
Allen hugged her and laughed: "Oh, you're disappointed."
The comedians and TV presenters are the latest pair of celebrities to research their family trees for the show.
Last time, Kate Garraway discovered she was related to Paddington author Michael Bond and had a relative who inspired James Bond author Ian Fleming to write his spy novels.
Her friend and ITV co-star Alison Hammond found out about an ancestor who had been instrumental in campaigning for the rights of free people of colour in Jamaica.
Next week, Gavin & Stacey co-stars Larry Lamb and Alison Steadman will go on the hunt for their surprising family connections.
The series has also featured Ant and Dec, Torvill and Dean, and The Chase stars Anne Hegerty and Shaun Wallace.
Dommett and Allen's DNA Journey episode airs on Thursday at 9pm on ITV.