Tom Cruise has said proof of his Irish roots is a great honour for him and his family.
In Dublin for the premiere of his latest blockbuster Oblivion, the Hollywood star was shown research that traces his heritage back to 12th century Norman knights. Researchers also described one of his ancestors as a "hero landlord" after records showed he restored evicted tenants to lands just before the famine in Ireland.
Tom said he had been taken aback by the depth of his family history.
"To learn about the history of my family - it was incredible," he said. "I knew I was Irish but I had no idea where it went and the depth of it. It goes all the way back to the 12th century."
The star added: "It's a great honour for me and for my whole family - I can't wait to bring it back to them and enlighten them on their history. I'm very proud to be Irish. There's a pride in America of being Irish. I can't wait to come back and I want to visit the land of my ancestors and the castle that they had."
Tom also had engagements with the Irish Film Board, a pre-recorded Late Late Show interview and a visit to the Guinness brewery during his whistlestop visit which began when Tanaiste and Foreign Affairs Minister Eamon Gilmore presented the star with a framed certificate of his Irishness at Iveagh House.
Genealogists, commissioned by Tourism Ireland on behalf of The Gathering - an initiative to attract the Irish diaspora to visit Ireland through 2013 - revealed the extent of the stars' Irish links.
The Hollwood A-lister, remembered for a cringing Irish accent in the 1992 film Far And Away, was a direct descendant of landlord Patrick Russell Cruise. His great-great-great grandfather returned from America to Ireland after his land agent forced families from farms in Co Westmeath in 1843. The landlord restored tenants to 500 acres around the townlands in Paristown and Dardistown in the years before the Great Famine when potato crops repeatedly failed.
The actor was born Tom Cruise Mapathor IV in 1962.
The research showed that the Cruise and Mapathor families had settled in Ireland, with roots going back 800 years while a third family, the Russells, were also prominent in Cruise's ancestry. The Cruises can trace their presence in Ireland back to the Anglo-Normans and Strongbow, Richard de Clare, earl of Pembroke and lord of Leinster.