The British ancestry of US celebrities, including Tom Cruise and Donald Trump, is revealed in immigration records.
Tom Cruise's roots are in Flint, north Wales
Cruise's Welsh roots and entrepreneur Mr Trump's Scottish heritage feature on passenger lists at Ancestry.co.uk.
About 100 million records show people who voyaged by ship from the British Isles to the US between 1820 and 1960.
The site's Simon Harper said millions of names "represent brave and colourful individuals who played a significant role" in shaping modern America.
Mr Harper, who is the site's managing director, added: "The fact that one in five Americans alive today is a descendent of the English, Irish, Scots or Welsh is testament to the survival and success of many of these passengers."
The records detail Tom Cruise's Welsh roots through his paternal great-great-grandfather Dylan Henry Mapother who emigrated from Flint, north Wales, to Louisville, Kentucky in 1850.
Halle Berry's maternal grandmother sailed from Liverpool
And the records show that Mr Trump's mother Mary MacLeod was born on Scotland's Isle of Lewis in 1912. She sailed for the America on The Transylvania in 1935.
The heritage of Oscar-winning actress Halle Berry is also featured, with records showing her grandmother was only nine months old when she set sail from Liverpool with her mother and five siblings in 1912.
And First Lady Laura Bush can also trace her roots to England. The records reveal her great-great grandparents sailed on the Southampton from London to New York in 1865.
The Ancestry Passenger Lists detail factors such as age, occupation, purpose for travel and even who funded the voyage.
People emigrated from all parts of the British Isles, many to escape poverty and hunger.
By 1860, the number of Irish immigrants arriving had made New York the largest Irish city in the world, making up a quarter of its 800,000 residents.
The lists, which will be free to view until November 30, also uncover stories of onboard romance.
They tell how 18-year-old William Smith met Margaret Rankin on board The Standard when they sailed from Belfast to New York. The love-struck teenager followed the 21-year-old to Brooklyn and they married in 1852.