Dannii Minogue’s former boss Simon Cowell has come out with an extraordinary account of a fleeting affair between the two.

Simon Cowell, 52, who loves nothing more than to polish his image as a ladykiller, has confirmed rumors of a fling in an “unauthorized” biography.

Sweet Revenge: The Intimate Life Of Simon Cowell has been written by respected author Tom Bower.

Tom Bower has not allowed Simon Cowell to read the final manuscript, but during hours of interviews it seems the two men became friends.

It is clear Simon Cowell is loving the attention of being presented as the pasha at the head of a talent show TV harem. “Yikes!” he tweeted triumphantly after seeing the newspaper headlines proclaiming “Cowell’s Affair With Dannii”. Smug barely covers it.

Simon Cowell has long suffered jibes and speculation about his sexuality. Just recently, the Village Voice in New York ran an article titled: Simon Cowell: Gay Or Just British?

The X Factor judge Louis Walsh has long enjoyed catty observations about Simon Cowell’s camp demeanor.

“He is camp, he is theatrical,” says Louis Walsh.

“He tilts his head just like a woman.”

Simon Cowell told Tom Bower he fell for Dannii Minogue after she joined The X Factor’s judging panel in 2007.

“It was genuine love,” Simon Cowell claims.

However, a long-standing friend of his said: “Whenever Simon uses the phrase genuine, you know it’s not true.”

His account of the romance is as follows: “I had a crush on her. It was her hair, the sexy clothes and the ***s. She was foxy. She was a real man’s girl. Very feminine.”

Simon Cowell says they got together in August 2007. An affair was rumored at the time. They were pictured holding hands in a car leaving BBC TV Centre, and Simon Cowell said repeatedly on the record that he “fancied” Dannii Minogue, though at the time they both denied anything had gone on.

“Every guy in the world fancies Dannii,” he said in an interview at the time. “She’s become a sex symbol since joining the show.”

Why did it end? Apparently, Simon Cowell told a friend: “There were a few bonks and then it petered out while I was in America.”

Not quite the stuff of grand romance, then.

Simon Cowell has never married and none of his many relationships has lasted. There have also been numerous flings and liaisons, which he has been lucky to keep out of the newspapers.

One relative of a Simon Cowell conquest said: “He is very intense and controlling, and then when he cools off he simply couldn’t care less. I don’t really know if he has ever been in love. He will say he is, but it’s not in his make-up, in my opinion.”

Another long-standing colleague says: “Simon is only fully committed to work, making money and to himself. It’s all about him.

“The only person he cares about other than himself – who he has ever cared about – is his mum, Julie.

“He likes pretty girls and being in a relationship, but they end up just being useful arrangements. He will never get married. That’s the way it is – it’s not the wrong girl or the wrong time, it’s just Simon.”

Dannii Minogue’s former boss Simon Cowell has come out with an extraordinary account of a fleeting affair between the two

In the book, Tom Bower says, perhaps more tactfully, that Simon Cowell felt he was not ready for a relationship with Dannii Minogue, having just split with long-term girlfriend Terri Seymour.

It’s all rather odd, though, as Simon Cowell and Terri Seymour split officially only in November 2008 – more than a year after the fling with Dannii Minogue. And, in April 2008, as rumors circulated that the relationship with Terri Seymour was over, Simon Cowell’s spokesman Max Clifford insisted that they were still a couple.

Now Max Clifford has changed his tune and claims they were, in fact, separated.

“Simon was single and Dannii was single and there was an attraction between them, so that’s life,” he said.

A friend adds: “He and Terri had split up a long time before they made the official announcement. They both knew what the situation was then and there was no problem with it on either side.”

Others, though, say that he has been an unfaithful partner.

Eighties pop star Sinitta, who dated him for a number of years and remains a close friend, has called Simon Cowell a “master of denial”. She caught him out several times with other women and described him as a “horny, salty dog”, saying he likes women of every color, culture and size.

Despite his affair with Dannii Minogue, when it later suited him to drop her as a judge from The X Factor, Simon Cowell did so without a backward glance.

Dannii Minogue, now 40, has just split from her partner Kris Smith and issued not a word on the subject yesterday. Her PR Simon Jones said: “I’m sorry, but I’m not making any comment on this story, on the record or off it.”

As she is dealing with her own romantic heartbreak and has been hung out to dry in order to make Simon Cowell look good, she could be forgiven for feeling pretty bitter about it all.

But then, as the many people whom he has picked up and shed along the way can tell you, Simon Cowell is an egomaniac of ocean-going dimensions. If it suits him to drop you, he will – even Louis Walsh was sacked from The X Factor panel and later reinstated.

If he thinks it helps his TV show to humiliate you, he will – witness The X Factor’s cannon fodder auditionees.

If he thinks it is good publicity to cast you alongside someone who hates your guts, he will.

Indeed, the revelation of an affair with Dannii Minogue sheds a fascinating light on the feud between her and fellow former X Factor judge, Sharon Osbourne.

Sharon Osbourne declared war within a few weeks of Dannii Minogue joining the judging panel and developed an almost pathological dislike of the younger woman.

She said only last year that Dannii Minogue was “****ing useless” and described her as “not so much a dim bulb as a power cut”.

Now we know she was jealous of Simon Cowell’s flirtatious preference for Dannii Minogue. He just sat back and watched them snipe at each other, thinking it amusing and good for the TV ratings.

Sharon Osbourne quit her job over it and Dannii Minogue was repeatedly reduced to tears, yet he never rode to her rescue. So much for “genuine love”. And if you thought the topic of his private life could not be any grubbier, then consider his “crush” on singer Natalie Imbruglia, another gorgeous Australian.

In his book, Tom Bower reveals that she was invited on the yacht Simon Cowell hired last New Year.

Allegedly, he hoped they could rekindle a former affair – but he got nothing more than a kiss and cuddle. After four days, the embarrassed singer left the ship.

It is worth remembering that at the time Simon Cowell was still with his fiancée Mezhgan Hussainy, known as Mish.

Mish Hussainy, once his make-up artist, told her family at the time that she and Simon Cowell were together, even as he was allegedly attempting to seduce Natalie Imbruglia.

She also had to put up with Simon Cowell’s pursuit of Cheryl Cole, which he confirmed to Tom Bower.

It was obvious to everyone watching The X Factor that he adored Cheryl Cole.

Simon Cowell used to put his arms around her during the show. Colleagues noticed they shared cigarette breaks and Cheryl Cole would often visit his dressing room.

With a tactlessness which is his trademark, Simon Cowell told an interviewer that it would be “a fantasy come true” to kiss her.

“When I’m sitting next to her, I forget everyone else,” he said.

Cheryl Cole said that he was so charismatic she felt he had put her in a trance. In the book, he admits: “I would have liked an affair with Cheryl, but I felt like a mouse being played with by a beautiful cat.”

In the end, Simon Cowell fired her from The X Factor USA after warning her to raise her game.

Did it ever occur to Simon Cowell that his pursuit of Cheryl Cole must have been uncomfortable for Dannii Minogue – and humiliating for his fiancée?

Perhaps it just didn’t. For Simon Cowell has a rhinoceros hide when it comes to such niceties.

There have long been rumors that he dates women on both sides of the Atlantic at the same time and the book would seem to add credence to them.

Simon Cowell had a romance with model Jasmine Lennard in 2006, during his relationship with Terri Seymour. She was seen arriving at his London house in a fur coat and high heels, and he took her to Ascot. And when it was all over, Jasmine Lennard disappeared – never to discuss the subject in public. Might she be one of the women whom he admits he has paid off?

He was certainly generous to Terri Seymour, buying her a house and paying for it to be refurbished by the celebrity interior designer Kelly Hoppen. There were also reports of a $5 million cash settlement for her – small change for Simon Cowell, who is worth more than $300 million.

His PR spokesman Max Clifford said: “Simon is naturally a very generous person.

“If he has spent a long time with someone and the magic has gone, but they have got used to a certain standard of living, then he feels they should have some money.”

What a curiously stunted emotional life Simon Cowell seems to have. He may be 52, but it’s all crushes and flings, like a teenager.

He says he is in love, but there doesn’t seem to be any room in his life for anything resembling it.