Reiniger was star of the 1978 film Dawn Of The Dead

Scott Reiniger, who appeared in the 1978 movie, is the great, great, great grandson of Josiah Harlan, the first American to set foot in Afghanistan.

As a result of a treaty Harlan signed, his heirs are granted the title Prince of Ghor in perpetuity.

Reiniger only found out his title after UK journalist Ben Macintyre published a book on his ancestor's life.

"My reaction initially was that it seemed incredibly surreal," Reiniger told BBC World Service's Outlook programme.

He discovered he was the prince of the western province of Ghor when his younger brother - who is named Harlan - emailed him after reading reviews of Macintyre's book.

WHO WAS JOSIAH HARLAN? Born a Quaker in Pennsylvania Started as a merchant seaman Jilted in Calcutta, swore never to return to US Headed to Afghanistan determined to become a king Contracted by exiled Afghan king to raise army Fermented rebellion in Kabul 'Invaded' in 1823 under US flag Became commander-in-chief of Afghan army Struck deal to become Prince of Ghor in exchange for army troops Thrown out of Afghanistan by British, returned to US Attempted to import camels to America Died in San Francisco on way to China

"I'd rather assumed that I'd done my best to track down his descendents," he said.

"But as [Josiah] Harlan had only one daughter, it was extremely hard to find them. And frankly we'd given up. So I was absolutely thrilled."

But Reiniger said he had no intention of claiming his title officially, and added that he felt his brother should have it anyway.

"He has the name and he's the historian in the family," he said.

"So I think he really should have the title."

Reiniger said he remembered his father talking about Josiah Harlan and also Alexander The Great when he was a child.

"He would demonstrate Alexander the Great's movements... sometimes he would pull out Josiah Harlan's sword, which my father had, and my brother now has," he said.

Kipling based The Man Who Would Be King on Josiah Harlan

He found Harlan had agreed a treaty with the Hazaras, the descendents of the Mongols who lived in the principality of Ghor.

Harlan was a Pennsylvania-born adventurer who travelled to Afghanistan in the early 19th century, having sworn never to return to the US after an incident in Calcutta left him stranded.

He headed to Afghanistan with the intention of being made a king. He soon met up with Afghanistan's exiled king, to whom he was contracted to stir up rebellion in Kabul.

He was skilled at playing two sides against each other and continually switched his allegiance. But his skill as a military general was noted and the Emir of Kabul, Dost Muhammad Khan, made him commander-in-chief of Afghanistan's army.

In the winter of 1839, Khan asked him to take on a prince on the other side of the Hindu Kush with 4,000 men, 600 camels and an elephant.

It would be a brave man who attempted to reassert his claim to be the Prince of Ghor

Ben Macintyre

It was during this expedition that Harlan stuck his deal with the Hazaras, and in particular - Refee Beg, the Prince of Ghor at that time.

Harlan agreed to return with a large, trained army with which they would conquer Refee's neighbours. In return, Refee agreed to hand over sovereignty over Ghor to Harlan, and his heirs, in perpetuity.

"The treaty remains in effect," Macintyre explained.

"Although it would be a brave man who attempted to reassert his claim to be the Prince of Ghor at this stage."