Comedian Lee Mack finds out more about his great-grandfather, who was also a comedian, known as Billy Mac.

Boy George expects to find sadness in his family tree, but delights in a new sense of his family being part of Irish history.

Shirley Ballas investigates her great-grandmother who abandoned her husband and children for a more exciting life in America.

Marvin Humes looks at his Jamaican and his English heritage, finding exceptional stories on both sides of the family.

Robert 'Judge' Rinder investigates his grandfather, a Holocaust survivor, and the dark mystery surrounding his great-grandfather.

Paralympian Jonnie Peacock looks back through the generations and ends up captivated by his four-times-great-grandmother.

Actor Daniel Radcliffe discovers that the Hatton Garden robbery of his great-grandfather's jewellery business was far more dark and dramatic than he ever imagined.

Actor Naomie Harris's dramatic discoveries in this episode inspire her to anger, sadness and tears of joy.

In a first for the series, father-and-son comedy double-act Jack and Michael Whitehall join forces to investigate their family tree.

Oscar-winning actor Kate Winslet follows a rumour of Scandinavian ancestry on her mother's side of the family and is delighted to find that she has Swedish heritage.

Canadian comedian Katherine Ryan's investigation of her family history leads her to a Methodist minister and his family in colonial Nova Scotia, cod traders in Newfoundland, and…

Paul Merton traces the life of his maternal grandfather and discovers that he was involved in some of the key events that led to Irish independence in the 1920s.

Sharon Osbourne uncovers the difficult circumstances of her mother's and grandmother's lives, and is stunned to learn that her great-grandmother was born in the US.

Former TOWIE star Mark Wright discovers that his ancestors included an Andalucian master swordsman and a Spaniard who was burned at the stake during the Inquisition.