"One celebrity uncovers an ancestor burned at the stake and another unearths a musical assault involving a banjo. From swordsmanship to solitary confinement, diamond trading to cod fishing and one American Dream gone wrong, the celebrities travel to the likes of Grenada, Jamaica, Sweden and Spain as they learn challenging truths and embark on extraordinary journeys."
Both Merton - real name Paul Martin - and Ryan have an Irish parent: his mother, and her father. Their other parents are English and Canadian, respectively.
Further details about the comics' journeys and findings in the series will be announced closer to broadcast.
Executive producer Colette Flight says: "We're delighted to have this incredible line-up of stars and to have captured these journeys of discovery as they explore their extraordinary family trees. What they uncover is revelatory, moving, often funny and always fascinating. Many of our celebrities' ancestors were caught up in momentous historical events which we are covering for the first time in the series."
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