Bruce Forsyth investigates claims that his great-grandfather Joseph Forsyth Johnson was married to two women at the same time and died at sea.
Actor Rupert Everett investigates his father's side of the family, beginning with a visit to his mother to find out about his grandfather Cyril's work in Nigeria for the Colonial Service.
Actress Dervla Kirwan traces her ancestry back to her great-great-uncle Michael Collins, who changed the course of history in Ireland as he fought to establish the Irish Free State, and uncovers her grandfather's part in events.
Gardener and TV presenter Monty Don researches his ancestry, beginning by investigating his great-great-grandfather, a vicar who had a parish in Nottingham in the 1840s.
Actor Rupert Penry-Jones investigates his family's link to India. He begins by researching the work of his grandfather, who was a doctor in the subcontinent's medical service, and travels to Italy to learn about his role in the campaign at Monte Cassino during the Second World War.
Comedian and actor Alexander Armstrong decides to follow up on suspicions that his family background is likely to be privileged, confirming his aristocratic roots by discovering the truth about a 'wastrel' ancestor who inherited a baronetcy from a cousin.
Actor and singer Jason Donovan investigates his mother's family line, in the hope of finding out about his Australian heritage and understanding the reason why she went missing from his life as a child.
Holby City actor Hugh Quarshie investigates his ancestry. Hugh knows there is a Dutch history in the family, but does not know where the bloodline began.
Actor Alan Cumming investigates the life of his maternal grandfather Thomas Darling, a career soldier who died in mysterious circumstances in Malaysia aged 35.