'Yes, I work in showbusiness, the business of show, but I work in a very serious business, a very hard business,' Jonathan Shalit tells me with his infectious enthusiasm.

"Behind all the glamour and the glitz, there are an awful lot of hours put into work to make sure my clients have careers. Talented people in front of the camera need talented people behind the camera to help guide their career.

"I suppose that 90 per cent is the unglamorous side that people don't know exists; 10 per cent is glitz."

Shalit has made a name for himself as the top talent agent to the stars. He famously turned unknown 11-year-old schoolgirl Charlotte Church into an internationally-acclaimed soprano - before being unceremoniously sacked and settling a multi-million pound dispute out of court in 2000.

Now, the ROAR Global founder's group looks after around 200 people, from business leader Baroness Brady to actress Joan Collins, who was signed up this week. And he calls many stars "close friends", inviting them for Shabbat dinner and dancing with model Kelly Brook, singer Myleene Klass and TV presenter Lorraine Kelly at his wedding to designer Katrina Sedley, which was officiated at by American Rabbi Mark Winer in 2010.

Celebrities, from Tulisa Contostavlos to Pixie Lott, were even pictured at his OBE bash last month, to celebrate his services to the entertainment industry. "The fact they're stars is irrelevant," he shrugs. "Whether you're an accountant or a lawyer, inevitably you become friends with the people you do business with. Because I work in a business where the names are more interesting, people tend to focus."

I met Shalit at his company's central London office on Charlotte Street. He was full of apologies for a 30-minute delay because of a client-related emergency.

We took a seat on the top floor room; complete with a brown leather couch, cowskin rug, flat-screen TV and full-length mirror.

The 52-year-old is exactly as he appears in the OK! magazine cuttings his assistant had placed before me: smiley, suited in black with a dash of red. "I always wear red socks, ever since I went on tour with Larry Adler in New Zealand in 1994," he says. "Why shouldn't men have a bit of colour, why only the women? I don't want to wear a purple or a red suit - that's ridiculous!"

Shalit is a showman, but his relationship with his artists goes deeper than schmoozing at parties. A West London Synagogue member, he's a self-professed proud Jew, Israel advocate and keen to ensure that the people around him know it.

"This hasn't been the best time for the Jewish people because of the complete misinformation that comes out of Gaza," he says.

"It's important that prominent Jews stand up and say what Israel is doing is right. In the past six months, British Jewry hasn't stood up, or been loud enough - or certainly those with a voice that matters. The world needs to know that Israel does not choose to kill innocent people, but are given no option because the cowards who bomb Israel day-in day-out surround themselves with innocent people. If someone threw bombs on London, the British military would retaliate. The British people would support the military defending London. But Israel gets condemned. It's double standards."

Shalit is acutely aware of the potential impact of his comments.

Over the Israel-Gaza war this summer, his industry associates who openly supported Israel were attacked by boycott activists.

"Well-known people are scared to visit and support Israel because the second you put your head above the parapet, [boycott] organisations bombard you," he explains.

"I have some very high-profile friends, some of the most famous people in the world, who support Israel and have been completely attacked on Twitter and had death threats. The Palestinian people have the upper hand on PR, projecting a false take on what is actually happening in Gaza."

He adds: "I can't say to my client, [perform in] Israel and harm your career. I can do what I want as a Jew, but I can't expect my clients to support a cause that isn't their own."

But he has managed to get some artists to back communal causes. As a Norwood supporter, who has a family member living in the charity's Ravenswood centre, he's the link that ties guest-grabbing performers to fundraising events.

And one Norwood dinner, five years ago, stands out: "It was because of a Norwood dinner that my marriage came about. I bumped into Katrina's best-friend. She said to me, 'you must call Katrina', and it prompted me to do so.

"For years I had girlfriends that weren't Jewish. I didn't set out to marry a Jewish girl. Finally, when I came to that moment, it was a Jewish girl's approach to life, what she stood for, what she represented, that I felt most comfortable with.

"If you marry someone of your own kind, you have more chance of it working. Wouldn't you agree?"

Shalit says he decided to pursue a career in the industry aged 18, in spite of the advice given to him by the late Jewish film director Michael Winner, his neighbour.

"Michael told me: 'You'll never make it in the entertainment business. Go and be a good Jewish lawyer or accountant'."

After a period as a broker at Lloyd's of London and then Saatchi & Saatchi, he launched his own consultancy and entered the entertainment industry - something "my mother still worries about".

Now, he's a visiting professor at Henley Business School, which his step-daughter Sofia mocks since he never went to university and attended eight schools as a teenager, ending with City of London Boys School. "Was that down to rebellion?" I ask. "Yes."

Shalit has come to resent the snobbery with which cultural institutions and "posh" critics have come to treat his clients, some of whom have come to attention on the back of reality TV shows such as The Only Way Is Essex.

"There is definitely some intellectual snobbery against mainstream British entertainment," he says.

"When you read an intellectual journalist or politician criticise a programme watched by millions, that's insulting people. When they criticise aspects of British entertainment, they criticise the people who enjoy it. Mainstream entertainment, which generates billions of pounds and is not subsidised by the state, doesn't get the recognition for the great and the good."

During our interview, Shalit tends to clutch on to his signet ring. A source - who also revealed that Shalit has a past JC interview framed at his home - claimed it's imprinted with a menorah seal.

"Who told you that?" he asks, eyebrow raised. "Yes, my dad was awarded a family crest with a menorah in the 1970s; so I decided to have a signet ring with a menorah on. It's personal. It's important to be proud of who and what you are." And the rumoured JC frame? "It's interesting. For my mother, I could be in The Times, The Telegraph - it means nothing to her. "In the JC, my mother is a happy Jewish mother."