A rabbi walks into the Vatican and asks the Pope....

A US rabbi has been appointed comedic advisor to the Pope. Rabbi Bob Alper was one of 4,000 people from 47 countries who submitted jokes in a competition ahead of Pope Francis' US visit last month.

Participants in the Joke with the Pope competition were asked to dedicate their joke to one of three causes - housing the homeless in Ethiopia, children in need in Argentina and feeding the hungry in Kenya.

Rabbi Alper shared his winning joke in a video he filmed on his phone: “My wife and I have been married for over 46 years. Our lives are totally in sync. For example, the same time I got a hearing aid, she stopped mumbling.”

Other participants in the competition, which had comedian Bill Murray as adviser, included actress and comedian Ellie Kemper, weather forecaster Al Roker and late-night TV host Conan O'Brien.

Entrants were asked to keep their jokes short and clean.

Fr Andrew Small, national director of the Pontifical Mission Societies in the US which organised the competition, said: "It was the kind of joke I think the Pope would use himself, and that's what befits an honourary comedic advisor."

Rabbi Alper (70) describes himself on his website as the world’s only practising clergyman doing stand-up comedy. He was ordained in 1972 and has worked for the last 27 years as a stand-up comic after 14 years as a full-time rabbi.

“For me, Joke with the Pope was doing good while having fun,” said Rabbi Bob. He donated his prize to helping to house the homeless in Ethiopia.

“It’s the joy of the mitzvah.”

As for being the Pope's comedic advisor, Rabbi Bob feels Pope Francis has already "got it."

“He exudes warmth, honesty – and there’s his humour,” he said. “We all benefit from his model.”

Due to the success of the campaign the Pontifical Mission Societies decided to donate a $10,000 cash prize to all three causes.