US Republican vice presidential candidate Sarah Palin is distantly related to the late Princess Diana and former US President Franklin Roosevelt.

The governor of Alaska and the princess are tenth cousins, while Ms Palin and President Roosevelt are ninth cousins once removed, according to experts from the genealogy website Ancestry.com.

The genealogical connections are not the first to gain attention in the US presidential campaign.

Last year, Lynne Cheney said she found while tracing her family roots that her husband, Vice President Dick Cheney, was a distant cousin of Democratic presidential nominee Barack Obama.

Other researchers discovered Obama is a distant cousin of actor Brad Pitt.

'When you've got candidates who have deep roots in America, there's a good chance that they're going to have some famous cousins,' said Ancestry.com's chief family historian Megan Smolenyak.

'We've all got literally millions of cousins. The trick is finding that one little connection that results in something like Sarah Palin being related to FDR or Diana,' she said.

Gov Palin and the late princess descended from John Strong and his wife Abigail Ford, according to the site.

Strong was born around 1605 in England and emigrated to the then English colony in America, where he died in Massachussetts in 1699.

Gov Palin and President Roosevelt share ancestor John Lothrop, who was born in England in 1584 and also emigrated, where he died in Massachussetts in 1653.

According to family and local histories, Mr Lothrop was a Puritan Presbyterian minister who arrived in the Massachussetts colony in 1634.