There was no 'Rabbi Beards' section in the Yellow Pages, so I tried 'Fancy Dress'. I rang Caribbean Carnival Costumes of Notting Hill, west London.
'We are all out of Rabbi beards,' said the man at the other end, 'but we have got a Rasta beard, how about that?'
I tried a shop in Hayes, Middlesex. 'Oh yeah, we've got lots of those,' said the girl. They were, she informed me, pounds 2.95 each to buy. And they were made of crepe.
I finally tracked down a suitable beard in Covent Garden, picked up a black Homburg at Simpson of Piccadilly, and took a taxi to the airport.
'Did anyone give you anything before you left the house?' asked the woman security officer at the El Al check-in. 'No one's given me anything since my bar mitzvah,' I told her. Then she opened my bag and found my beard and moustache. 'It's an emergency,' I said. 'A big wedding. The rabbi's got alopecia. He's desperate.'
She started to talk into her sleeve. Young men with large-shouldered jackets stopped asking Orthodox Jews to lift up their hats and gazed at me intently. 'Do you have any Jewish friends, Mr Rosengard?' asked the officer. I had been waiting all my life for someone to give me this cue. 'Actually,' I said, 'some of my best friends are Jewish.'
In the taxi from Tel Aviv to Jerusalem I started to glue on my beard. In my wife's hand-mirror I looked like a cross between Moses and ZZ Top. A few miles outside Jerusalem the driver took a look in his mirror, slammed on the brake, and ran off into the night. I ran after him, found him behind a bush, and managed eventually to assure him that I wasn't a spy.
In the lobby of the Sheraton Plaza, I sat self-consciously behind a newspaper while my wife checked us in. She came over to me. 'Wait a minute]' she said. 'You're OK - nobody would recognise you. But what about me?'
She had a point. She is Chinese, and 5ft 10in tall. My parents might just have recognised their daughter-in-law.
'You can wear the moustache,' I suggested.
I borrowed a jacket from a waiter and a tray with two cups and took the lift up to my parents' room. There were six other men crowded into the lift. We all had big black beards, moustaches and big black hats. Somehow I still felt different. The lift was slow. It was very hot. I started to sweat and felt glue running down my cheek. A little blonde girl stared silently at me as half of my beard peeled away from my face. I raised my eyebrows, gave her my 'It's a funny old world' shrug, pressed my face against my shoulder and, when the doors finally opened on the 12th floor, pushed my way out of the lift like the Hunchback of Notre Dame, all the while carrying the tray in front of me.
I knocked on my parents' door. 'Room service,' I shouted in my best Israeli accent. My father opened up. 'Hello, Peter,' he said.
A longer version of this article appeared in the 'Jewish Chronicle'