Shergar, County Louse - The Hollywood actor's roots have been traced to degenerate fairy folk according to Irish gynecology - er... genealogy! - specialists at a Dublin PR ceremony this morning.
"It's where you get your legendary stature from," an Irish Tourism Board official suggested helpfully as the 4ft 6in film star posed for cameras ahead of tonight's world premiere of his latest movie Oblivion.
Researchers found the Cruise genome stretches back all the way to the Irish Potato Blight famine when the wee fairy folk were forced to mate with Scandinavian trolls to secure their dwindling bloodlines.
Their resulting descendants, the leprechauns, suffered a vast array of physical deformations - 'mostly undescended testicles' and other stuff 'such as congenital delusions of being able to act'.
The news comes just weeks after US President Barack O'Bama claimed direct Irish lineage going all the way back to the Book of Invasions, a medieval folklore manual listing all known Irish wizards who escaped detection by the English Domesday Book of apocalypse-peddlers.
Cruise joins other Hollywood pros including Ben O'Stiller, Charlie McSheen, Johnny O'Depp, Ashton MacKutcher, Mariah O'Carey, Ben d'Affleck and Anne McHathaway in the pantheon of Irish-rooted stars.
Top Irish-American blarney spouter Bill O'Clinton once shagged the Empress of Ireland.