If there is anyone who understands the agony of being berated by the X Factor judges, it is Brian Friedman.

As creative director of the show that has unified the nation in a TV ritual which ends this weekend with its grand final, Friedman knows what it's like to be panned as well as any of the contestants - only in his case, it is his staging and choreography that is the target. For that reason he felt enormous empathy with Katie Waissel, who was voted off the show two weeks ago, and puts a lot of his concern for her down to that "Jewish thing".

"It's that indescribable bond that Jews have, particularly when they are under attack," says the 33-year-old American-born choreographer, who is always seated in the audience to watch the results of his week's work. "She had a tough time and it was awful because I think she is very talented and knew better than most how to deliver a song. It was easy for me to work with her and get results."

Friedman has learnt a lot working on X Factor, particularly how to read what he calls Simon Cowell's "eyebrows of disdain". "When they rise, I know I am about to be scolded for something," he says.

Cowell's eyebrows tend to arch skywards at the sight of a complicated dance routine, overly sexy background dancers, excessive use of vehicles, swings or rollerskates. It was the rollerskates worn by contestant Diana Vickers and her supporting dancers that caused Friedman real bother. "That was arguably one of the worst routines I've ever seen in my life," said Cowell, backed up by fellow judges Louis Walsh, Danni Minogue and Cheryl Cole.

I know when Simon's eybrows rise, I'm going to get scolded

"I laugh every time I get slagged off on the show," says Friedman. "I am the one who gets trashed if things aren't to their liking and I'm constantly accused of copying big-star routines. But what they forget is that I've choreographed routines for Britney Spears, Beyoncé, the Pussycat Dolls, Usher, Pink and Mariah Carey.

Mention a major performing artist and chances are that Friedman has mapped out every turn and back-flip of their tour show and video. When Janet Jackson performed a dance tribute for her brother Michael at MTV's Video Music Awards last year, it was Friedman who was dancing beside her.

"It was fantastic to share that moment with her and an honour to dance in his memory," he says. Friedman first worked with Jackson as a 14-year-old. "I stood with him backstage looking at the audience. Michael was always blown away by the sheer number of fans."

Of course, working with top performers is a lot easier than trying to make the untrained and "mostly unco-ordinated" X Factor finalists look polished when he has only 20 minutes to teach them a routine on Tuesday afternoons. "The work is beyond difficult and I age 10 years every season, " says Friedman, who grew up in Scotsdale, Arizona in a family he describes as "warm and welcomingly Jewish".

"My father was happy about me dancing, but he never came to terms with the fact that my classes coincided with cheder and eventually I gave up the idea of learning Hebrew at all. Instead of a barmitzvah, I had a recital."

Friedman's mother, whom he describes as a "master of guilt and over-feeding", encouraged him all the way and they even ran a dance studio together, which he did in tandem with being in a pop group with his best friend, the late actress and singer, Brittany Murphy.

"We were called Blessed With Soul, if you can believe that," he laughs. "We were so close as kids and she was the strangest child you could ever meet, she had so many 'isms'. She touched everything she walked past. She had more energy than Jedward, it was like a light shone through her. I was devastated when she died of an overdose. That and Michael Jackson's passing have been pivotal events in my life."

The creative director, who also holds the same job on America's Got Talent, is hedging his bets on the outcome of Saturday night's final, but he did predict good results for Rebecca Ferguson, Matt Cardle and One Direction, though was less sure about Cher. "It will be a strong competition, but the line-up is not a choice I agree or disagree with," he says diplomatically.

Disagreeing with Louis Walsh has been a nagging constant since Friedman replaced him briefly as a judge in 2007. "Simon brought me in because of what I do with artists, but Sharon Osborne didn't take to me. She just went on about missing Louis and didn't ever give me a chance," he recalls. "Simon was always great with me and we hook up for dinner when he is in LA, but Sharon wasn't having it."

Walsh bad-mouthing Brian publicly as someone "the British public wouldn't get" did not help and that continued when Cowell decided to utilise Friedman for his staging talent, with Walsh commenting: "I don't know what a creative director does."

He certainly should now - all of the judges have been waxing lyrical about Friedman's big-stage showdowns over the past few weeks, notably his stirling work with the Brazilian contestant, Wagner, who went out the same week as Waissel. "He was the hardest artist I have ever had to work with, and had dubious personal hygiene," sniffs Friedman.

Although he switched from judge to creative director, Friedman wisely negotiated to hold onto his reputed £500,000 per series fee. "I made sure I kept the judge's salary," he smiles, and is content that now everyone sort-of gets along on the show, though he insists that the tension on the panel is not pantomime. "When nasty things are said, it's not always easy to forget them," he says. "I have done 15-hour days for weeks and it's exhausting, particularly as I started boot camp 12 hours after having major surgery on my shoulder."

A cut in the X Factor budget mid-season has meant he has had one less day in the studio to rehearse. "The rationale is that there are less contestants, but the expectations are higher, particularly for this weekend's finale, so it's nerve-wracking for me because it's all been on my shoulders, and one of them still hurts."

To relax, Friedman likes to party and attends as many red-carpet events as he can in London, usually accompanied by Israeli socialite Hofit Golan. "She likes to be seen out as much as me " he says, though how much longer he will be gallivanting about town is debatable as he is earmarked for joining Cheryl Cole and Cowell in the United States when The X Factor starts there next September.

"But there are so many people in the UK that still want to work with me, and I don't think I have heard the last from Katie. She and I really bonded.

"I am sure I will be back to put the next bunch of contestants through their paces again, regardless of the criticism - I can handle it."