NBC, Fox, ABC and CBS are all competing for the programme rights. Discovery, National Geographic and the History Channel have also shown a strong interest.

They hope that it will match the success of other UK imports such as Pop Idol and Strictly Come Dancing.

CBS has already proposed a prime-time special to launch the show with Julia Roberts as the first participant.

A desire to find out more about our past, driven by easy-to-use websites, has turned genealogy into big business.

One in ten internet users visits a family history site each month. Yet the BBC was surprised when celebrities investigating their roots proved a hit. It rejected the idea 15 years ago. Now the emotional journeys of discovery on Who Do You Think You Are? attract six million viewers to BBC One.

Its discoveries often stun participants. Bill Oddie confronted his mother’s illness and discovered that he had had an older sister who died within days of her birth. Paxman broke down on camera after learning the circumstances of the death of his great-grandparents, through TB and exhaustion.

Ms Roberts was born in the US state of Georgia after her parents moved there in the 1960s and opened an acting school.

As a child she spent summers with her uncle in Bemidji, Minnesota. Bemidji, meaning “lake with cross waters”, borders the Mississippi River and boasts a proud native American heritage.

It is hoped that other stars would also be prepared to take part in the programme.However, questions remain over whether celebrities protective of their images, would open themselves to potentially shocking disclosures.

Alex Graham, head of Wall To Wall, the London independent production company that created the show, said: “It is very important the celebrities discover the information on camera. The emotion is always authentic. Celebrities do not have editorial control over the results of their search. They can ask us to remove scenes they feel are intrusive, but no one has so far.”

Mr Graham said negotiations were continuing with US broadcasters. But the British producers want to protect their brand and make the shows themselves. Versions are showing in Canada, France, Poland, Germany and Australia.

Peter Fincham, the Controller of BBC One, said: “It assumes a mainstream audience will be interested in the difficulties faced by the Armenian community in Istanbul in the last century, or the genetic make-up of families who emigrated from Jamaica to Cardiff. And what do you know? They’re right.”

Production has begun on the fourth BBC series. Mr Graham’s ideal participant? “It would be interesting to get Sacha Baron Cohen,” he said. “He might discover that he has ancestors in Kazakhstan.”

WHERE TO RESEARCH YOUR GENEALOGY

genesreunited.co.uk: 50 million names listed, crosschecks your family tree with others to find a match

ancestry.co.uk 300 million names in database and every English census document from 1851 to 1901.

www.scotlandspeople.gov.uk: Scottish censuses

www.genuki.org.uk: British and Irish family history with 60,000 pages and a section for each county in the British Isles

nationalarchives.gov.uk: Census records, family, local and military history

familyrecords.gov.uk: Helpful links for the beginner

gro.gov.uk General Register Office — birth, marriage and death certificates. Order online at £7 a time

Times Recommends

• Riots as Zimbabwe turns off water supply
• Tourists told to stay away amid Venice floods
• Protest is no picnic for Carrefour customers