By Paul Burnell
The One Show
Some years before Barack Obama began his run for the White House he found himself on a pub crawl in England helping give a traditional British send-off to a nervous bridegroom.
Barack Obama has an unlikely connection with Bracknell
He is the man who could be the first black president of the United States. But for Ian Manners, Barack Obama is the guy who turned up for his stag night.
Ian was marrying Mr Obama's half-sister, whose mother Kezia Obama was the first wife of the senator's Kenyan-born father.
When the presidential hopeful's own mother Ann Dunham died, he strengthened links with his extended step family. Barack and Kezia, who lives in Bracknell, Berkshire, first met in 1987 in the Kenyan capital Nairobi.
"He looked like his father - he was very smart and good looking," she told BBC One's, The One Show.
Mother and step-son became close and some years later, when he heard his half-sister Auma was getting married, Barack Obama decided to make the trip across the Atlantic for the wedding.
And this is how Harvard-educated Obama, who was a civil rights lawyer at the time, ended up on a pub crawl in 1997 in Wokingham with Ian Manners.
Then in his 30s, Mr Obama found himself witnessing the British ritual of the pre-wedding humiliation of the bridegroom. Ian and his friends had just moved to a pub called The Rose, when the predictable happened.
"When we got there we had a couple of drinks. Then there was a bit of a commotion and they sort of directed me into a back room with one exit," recalls Ian.
"Lo and behold, a strippergram turned up. She was a St Trinian's school girl."
"As she started I saw that he [Obama] was making an exit. He obviously saw my embarrassment because I was marrying his sister."
Soon afterwards the man, who could within the year be elected to the most powerful job in the world, decided it was time to return to his hotel room.
Barack Obama at his sister's UK wedding
Ian has no doubts his stag guest is presidential material.
"I'm not a gambling man but it is worth a good bet. I would put money on it," he says.
While in Bracknell, Kezia, like a lot of US voters, is hoping that a higher power will sweep 46-year-old Mr Obama into the Oval Office.
"God is there with him. I pray for him. He will be a good president."
To learn more about this story watch The One Show, BBC One, 1900 GMT, Tuesday 29 January 2008.