Bake Off star Mary Berry, still going strong at 79, believes she inherits her energy and drive from her father and sets off on a journey to find out more about his family. Along the way she discovers illegitimacy, bankruptcy, and even more astonishingly, a baker.

Actor Brian Blessed has always loved his unusual name but has no idea where his Blessed ancestors came from. Born in Yorkshire, he'd always assumed his family were northerners but, digging deeper, Brian discovers that his roots lie down south. Here he uncovers the story of his great-great-grandfather, Jabez Blessed - a tale of hardship, struggle and survival worthy of Oliver Twist.

Actor Martin Shaw never knew his grandfather, Edwin Shaw, who walked out on his family when Martin's father was just a boy. Martin sets off to find out what happened to this elusive character with his only clue a photograph of Edwin as a young man. From a shotgun wedding to the Birmingham Blitz, Martin tries to sort fact from family fiction to discover who Edwin was.

Scottish comedian and actor Billy Connolly has always considered himself Scottish through and through but as he travels to India in the footsteps of his army ancestors, he makes an extraordinary discovery. Not only was his great-great-great-grandfather present at a pivotal point in Indian history, through him Billy's connection to India runs deeper than he had ever imagined.

Twiggy grew up in London but her parents told her nothing at all about her family. She finds out about a history of strong women as well as a hint of crime.

Bafta-winning actress, Julie Walters of Educating Rita, Mamma Mia! and Harry Potter fame, traces her roots back to County Mayo in western Ireland, where her great-grandfather, Anthony Clark was one of the first members of the Land League. The organisation was formed in 1879 and campaigned for more than 40 years for the rights of tenant farmers to own their own land.

Actress Sheridan Smith has grown up surrounded by a musical family, singing with her country and western duo parents since she was a child. Sheridan is keen to know where her musical talent comes from and is soon hot on the trail of her great-great-grandfather Benjamin Doubleday. She's shocked to discover the dramatic fall in fortunes of this self-styled musical impresario and famous banjoist.

New Tricks star Tamzin Outhwaite has always been intrigued by her Italian ancestry. Although she remembers her grandfather Remo, she knows very little about his family. Tamzin's journey into her Italian past uncovers the rags-to-riches tale of her great-grandfather, Adelmo and takes her on an unexpected trip.

Brendan O'Carroll ditches his alter ego, Mrs Brown to turn detective, as he attempts to track down the men who murdered his grandfather at the height of the Irish War of Independence. Brendan never knew his grandfather, who was shot dead before he was born, and the only clues he has to go on are from a newspaper article of the time.

Presenter and DJ Reggie Yates grew up knowing very little about his father's side of the family. Reggie sets out on the trail of his grandfather, Harry Philip Yates. His journey takes him to Ghana, where he unravels a complex family history where Ghanaian culture and British colonialism collide.