Andrew Lloyd Webber is a global superstar of musical theatre, still writing and producing blockbuster shows. He has also combined his nose for business with his love of architecture by renovating the Theatre Royal Drury Lane to its original condition. Andrew knows he comes from a musical family, including virtuoso cellist brother, Julian – but he'd love to find out where his showbiz genes and his love of musical theatre come from.

A quick investigation of his own archive reveals a much posher lineage than expected. By following his mother's line, Andrew soon uncovers his four-times great Uncle Peregrine, who played a key role under Wellington at the Battle of Waterloo. Peregrine in turn leads Andrew to his 12-times great-grandmother Katherine Willoughby, a Tudor duchess and powerful player in Henry VIII's court who was later persecuted and threatened with death for her religious beliefs. As her dramatic life unfolds, Andrew is not only astonished by her determination and resilience but delighted to learn of her association with some of Britain's most architecturally important stately homes.

Next, Andrew investigates his father's side – a much humbler line, with both his grandfather and great-grandfather working as plumbers. With the help of his cousin Anne, he discovers his two-times great-grandfather Henry Simmonds was a missionary who dedicated his life to helping the poor and needy. Described as a ‘real working-class hero', Andrew is thrilled to find out that Henry was the author of the first architectural guide to Battersea.

Andrew still wants to uncover any musical links, and with the help of genealogist Laura Berry, he finally traces more musicians in the family, including his five-times great-grandfather Henry who has the curious surname Magito – which Andrew soon learns is Dutch. What follows next is a series of extraordinary resonances with Andrew's own life - an extended family of Magitos, who were not only accomplished musicians, but also showmen and producers making their living by staging the 18th-century equivalent of musical theatre.

But the coincidences don't stop there. More investigation proves his five-times grandfather Henry Magito had a brother, Alexis Magito, who was also a cellist. A trip to Leiden uncovers a long-lost sonata written by Alexis that reveals he was an accomplished composer and player for the cello. Andrew can't wait to return to London to meet with his younger brother Julian and share the extraordinary coincidences of their shared ancestry.

As an adventurer, wilderness expert and chief scout, Bear Grylls has travelled to some of the most hostile environments in the world, sharing his survival secrets with audiences of millions. Bear is curious about a tendency to ‘follow the path less trodden' so he's now embarking on a journey into his family's history. The trail starts at home where, alongside his wife Shara, Bear explores his paternal grandfather Ted Grylls's old trunk, intriguingly full of documents marked ‘Top Secret'!

Bear heads to Sandhurst Military Academy where his grandfather Ted trained to be an army officer in the 1920s. Here Bear discovers Ted's fascination with all things mechanical – especially tanks. With help from the team at the British Tank Museum, Bear learns how Ted became one of the British Army's biggest experts in armoured vehicles and tank warfare, advising both the British and Americans on how to win on the battlefield and contributing to the success of the D-Day landings.

But it's Ted's job leading top secret organisation T-Force that helps Bear really understand the pressures his grandfather faced and reveal clues about his character. Charged with identifying, tracing and sometimes even kidnapping Germany's best scientists for interrogation by the Allies after the war, Ted had to stay in Europe long after World War II was over, working on a morally complex mission, far from his family.

Bear also wants to find out more about the life of his beloved, ‘bear hug of a man', grandad Neville. Neville's father and Bear's great-grandfather, Lionel Ford, is revealed to be a loving family man and progressive headmaster who modernised Harrow School. In Harrow's Headmaster's House, where his grandad played as a boy, Bear discovers the truth behind a family tragedy – the death of his great uncle Richard, who died of an infection as a teenager. As a father of three boys himself, Bear is moved to read Lionel's own words about his grief and love for a lost son.

Finally, following his family line back several centuries reveals, to Bear's delight, Scottish ancestry. His habit of walking the dog in a kilt no longer feels fraudulent! A trip to Scotland uncovers the story of Bear's ten-times great-grandfather the Duke of Argyll, whose religious beliefs and devotion to Scotland cost him his head, courtesy of the Scottish maiden, a gruesome type of guillotine. And at his last destination, his mum's dreams of a royal connection come true. At the Argyll Mausoleum, Bear discovers his 21-times great-grandfather is none other than a famous Scottish king.