I once walked around the streets of Manhattan with Donald Trump.

It was an extraordinary experience. Everywhere we went, he was mobbed by ecstatic New Yorkers and tourists.

All cheering, shouting his name, fist-bumping if they got close enough and frantically demanding selfies.

It was like being with a rock star.

And in many ways, that’s exactly what Trump is.

He’s big, brash, bold and bombastic. But he’s also a major star; arguably the most famous businessman in the world, and host of a long-running, very successful TV series, The Apprentice.

On Tuesday Trump announced he is running for President.The reaction was almost comically predictable. Much of America’s mainstream media rose up in indignant outrage to say what a clown he is, whilst simultaneously packing Trump Tower where he made the announcement

Let me declare an interest here: I won Trump’s first season of Celebrity Apprentice seven years ago. Since then, we have become good friends and speak on a regular basis.

I like him. He’s smart, funny, loyal and thoroughly entertaining.

And he’s no political fool. I interviewed him many times during my tenure at CNN and on the myriad big issues facing modern America, he often makes a lot of sense.

Yesterday, Trump announced he is finally running for President, after years of flirting with candidacy then pulling out at the last minute.

The reaction was almost comically predictable.

Much of America’s mainstream media rose up in indignant outrage to say what a clown he is, whilst simultaneously packing the hall where he made his announcement, and then running acres of coverage on TV and in newspapers analyzing it.

Secretly, they all love him – because he’s box office. He sells papers and gets ratings.

Being around Donald Trump is like being with a rock star. I won the first season of Celebrity Apprentice and since then, we have become good friends and speak regularly. He’s smart, funny, loyal and entertaining

Trump both craves and commands attention.

He knows how to work the media, and they either wittingly or unwittingly, get well and truly worked.

He’s been thoroughly dissected by reporters, professionally and personally, for decades – so won’t have any fears about the kind of forensic examination that instantly engulfs all new candidates.

He also has a big popular appeal away from the snobby halls of Washington and New York’s media elite.

Regular Americans love the guy. He’s what America used to be all about – incredibly well resourced, a fierce patriot, gutsy, and bursting with ‘can-do’ confidence.

During the time I’ve spent with Trump, I learned a few interesting things about him.

He doesn’t drink. In fact, he’s never had a drop of booze after watching his older brother Fred succumb to an alcohol addiction.

He’s never smoked either – Fred was a 3-packs-a-day man - nor taken illegal drugs.

Trump doesn’t even drink coffee because he feels no need for any artificial caffeine-fuelled high.

All this shows a man with an unusually high level of self-control.

He may sound a little bonkers occasionally, but everything he does is deliberate.

On a personal level, he’s a terrific father to his five children, as I’ve seen at first hand many times. He loves and respects them as much as they love and respect him.

His only vice, as he once told me with pride, is women.

But let’s face it, that didn’t harm Kennedy or Clinton.

And his third, current wife Melania is a delightful lady.

Trump doesn't drink and his only vice - as he once admitted to Piers - is women. His third wife Melania, pictured Tuesday with their son Barron, 9, is a delightful beauty

His 45-minute speech yesterday was classic Trump.

Unleashing the simple, effective slogan “Make America Great Again’, he didn’t shy away from his wealth , as Mitt Romney did.

He embraced it enthusiastically and used it as a vote-winning weapon.

Only Trump could boast ‘I’m really rich!’ as a presidential candidate and get away with it.

But that boast carries with it a very serious significance.

Trump is a multi-billionaire, who won’t have to worry about campaign funding.

He also currently employs over 20,000 people, allowing him to declare with some justification: ‘I’ll be the greatest jobs president that God ever created.’

And when he gets mocked for suffering several corporate bankruptcies, he points to the way he recovered as evidence of an ability to force through difficult times and come out a winner again.

That’s hardly a negative, is it?

I don’t agree with everything Trump believes in.

As Trump says, he's rich. Really rich. He wont' have to worry about campaign funding and employs 20,000 people. He even waved around his financial forms to prove it

He's a fantastic father to his children, as well, and Americans love him. At left son Eric and his wife, youngest son Barron, Don Jr with his wife and their two eldest children, daughter Ivanka and her husband Jared and far right Donald's daughter Tiffany, by second wife Marla

He’s very pro-gun, for instance; he belittles any talk of science-based climate change; and he’s prone to occasional wild claims and exaggeration which merely serve to provide ammunition to his many critics.

But Trump’s right in his constant efforts to warn Americans about the dangers of China’s increasing economic might; he’s right to regularly grill OPEC over oil prices; and when he says he’d go big and hard against ISIS, I not only believe him but I reckon most Americans will applaud him for saying it.

Trump’s self-evidently a world class negotiator, something at which Barack Obama has proved to be very weak.

And he’s reputedly a man of his word when he does deals, a very important virtue when straddling the world diplomatic and military stage.

I have no idea if Donald Trump can actually win the Republican nomination, let alone become President.

But I do know this: he’s a fantastic candidate because he’ll electrify the tediously long U.S. election process, light up the Republican debates, and go after rivals in his own party and the Democrats with the same fearless aggression that he goes after those who cross him in business or on Twitter.

That will force them all to raise all their games, not to mention their hackles, and the quality of the race will be better for it.

Unlike most politicians, what you see with Trump is what you get.

He doesn’t pretend to be something he isn’t, or espouse things he doesn’t genuinely believe.

He’s the same in front of the cameras as he is away from them; a loud, chillingly confident, dynamic, compelling and polarizing character.

But under-estimate him at your peril.

I look at the current Republican field and think it’s rather dull.

I look at the wider election battle and see yet another Bush squaring up against another Clinton and stifle a yawn.