Jack Thompson looms large in the Australian imagination from such iconic films as Breaker Morant and The Man from Snowy River. Born John Hadley Pain in Sydney in 1940, he knows very little about the history of his biological family. When his mother died, Jack was sent to a local boarding school as their father Harold was unable to look after them. Eventually Jack was adopted by the Thompson family and he took their name. For the first time, Jack Thompson, legend of the Australian screen, discovers the history of his biological relations and the importance of us knowing our own stories.

Kate Ceberano made her name as a pop princess in the 1980s. She has sustained her singing career since then, touring for the past 20 years. Recently she has plunged back into the national limelight as winner of the 2007 series Dancing with the Stars. Turning 40 years old has become a watershed in her life. Kate wants to stop her hectic schedule and look back for a moment and find out more about her family’s past. Whilst looking Asian - her Hawaiian born father is third-generation Filipina - Kate has always felt Anglo and yet knows little about this side of her heritage.

She starts to understand why she is who she is, and answer many mysteries that she’s been longing to find an answer for.

Geoffrey Robertson is one of Australia’s best-known expatriates. The UK-based human rights advocate and occasional Hypotheticals presenter has been mixing with the famous and infamous ever since he exploded onto the swinging sixties scene to help defend the Oz magazine obscenity case. "People often come up to me and say 'Oh you Australians are so refreshing.' What they mean is 'Rack-off you loud-mouthed colonial.'" He is the consummate self-made man and his razor-sharp legal mind gives short-shrift to the nature-nurture debate. Genes don’t fit his world view.

But when he starts looking into his family tree in Who Do You Think You Are?® he finds some remarkable parallels in the expatriate lives of his forebears. Is Geoffrey Robertson the descendant of a right royal bastard or a very wiley entrepreneur? The jury is still out.

Dennis Cometti is the best known and most authoritative Australian Rules football commentator in Australia. Millions of football fans around the nation admire and respect his droll, quirky commentary. He knows everything there is to know about the genealogy of the AFL, confidently recalling any player’s pedigree, background and performance statistics – he spends hours researching the history of the game. But ask the ‘footy statistic guru’ about his own family and it is an entirely different story. He claims he has never had time to look into his own history.

Dennis wants to reconnect with his Italian identity. Everyone else identifies with him being Italian and he’s bemused because he doesn’t - he can’t even speak the language. Who Do You Think You Are?® takes Dennis on a journey to explore his rich Italian heritage.

Ita Buttrose is a trail-blazer – the first female editor of a major newspaper in Australia, a publisher, broadcaster and campaigner of equal opportunity for women. She’s promoted health issues, the needs of family and Australia’s ageing population. She’s always had a passionate interest in her family’s history, particularly in trying to unravel why her family changed their name from Butters to Buttrose, but has never had the time to investigate. Driven by the fact that many of her immediate family have creative and “nomadic” lives, she’s curious to find out whether these are ancestral traits.

Ita was made an Officer of the Order of Australia in 1988.