Simon Cowell delights in the fact that his son Eric is a mini version of himself.

It thrills him when Eric – a frequent visitor to the Britain’s Got Talent set – sits in his seat and does a bit of ‘judging’.

He laughs about how he asked Eric, five, recently if he’d like a job doing what Daddy does.

‘He said, “What do you mean? I already have a job. I come to the studio, don’t I?” I had to point out to him that there’s more to what I do than just pitching up.’

Perhaps we all like to see our children as miniature versions of ourselves, but Simon takes this to the extreme.

He loves to watch his own favourite childhood films with his little boy. He marvels at the physical similarities.

His parenting model is to look at his own childhood, in Elstree, Hertfordshire, and try to replicate it, give or take the odd yacht.

It’s tricky, though, since his parents encouraged him to work from the age of eight.

‘I’d do things like wash cars for people, but I can’t really send Eric out asking if people would like their cars washed.’

He’s baffled when Eric seems to be doing things differently to the way he did them.

‘He likes school, which is surprising because I never did,’ Simon admits. ‘He says he likes learning.’

And he openly admits he would love his son to one day take over his media empire. He is ‘training him up’, he says, half-jokingly.

Should we be surprised Eric was very nearly a Simon Cowell Jr, in name too?

Eric is named after Simon’s father, but when his mum Lauren was pregnant, Simon was contemplating giving their baby his own name.

Eric is here today as Simon’s chatting. He asks him if he’d rather have been a Simon.

Eric plumps for Eric, and his dad roars with laughter. ‘It’s just as well I didn’t inflict it on him.’

Did Lauren veto this idea? ‘Yes, but I did want him to have my dad’s name. I do think we made the right call. It would have been too much to inflict Simon on him.’

This is increasingly obvious now Eric is at school. Having a surname that makes him stand out is one thing; having the Christian name might have been too much.

‘And him being bullied is what I dread most. There are two things that worry me about him growing up.

‘One is stress. Children are under so much stress – with homework, pressure. I really don’t want that for him.

‘The second thing is bullying. It terrifies me. If there’s even a whiff of it… I don’t think I could handle it.’

We shouldn’t be surprised at his genuine fear.

Even Simon probably wouldn’t quibble at the idea that there is something of the control freak about him. And what parent truly feels in control?

Simon is opening up about his parenting preoccupations today in an interview promoting his latest venture.

In a rare foray into the advertising world, he has agreed to do a commercial with Barclaycard.

The campaign is focused around Barclaycard credit cards, and a push to advise customers how they can limit the amount of interest they pay.

The advert plays on the idea that it’s unthinkable – a bank going out of their way to take less money from you.

‘I don’t normally do adverts, but this one appealed because it was an interesting message, and done in a fun way.

‘The premise is that what Barclaycard are doing makes as much business sense as me going to Antarctica to find talent.’

So did he actually go to Antarctica to film? Alas no. Simon Cowell is more of a Malibu type guy, but the location shots are convincing.

Why on earth is he doing an advert, though? He can’t need the money?

‘It was fun,’ he says. ‘And it’s an important message. We could all do with a bit of advice on how to be better with our finances.’

But he has hundreds of millions in the bank. Surely he doesn’t fret about whether he can save £2 a month in interest charges?

‘You’d be surprised,’ he quips. ‘We can all learn something.’

Talking to Simon Cowell about being careful with money is akin to talking to an eskimo about sunscreen.

While he has been on his uppers – he famously moved back in with his parents when his business failed in his 20s – he is known for his lavish lifestyle.

He has a number of homes in LA and London. How many cars are we up to, Simon? ‘More than one,’ he jokes.

While he may have several cars, he can’t be accused of being scattercash in other areas.

‘I only have two watches,’ he points out. ‘People assume I have more, but no. I don’t have a lot of jewellery at all.’

After every successful deal, he says, he might ‘treat himself’ with a purchase.

And not some socks or a bottle of wine. Another car. He says that nearly being bankrupt in his 20s has meant he will never be blasé.

‘I almost lost everything, and so I never take anything for granted.’

With a reported £436 million fortune, he should be safe. And he has been throwing some cash around – well, professionally, anyway.

Last year it was reported that Simon’s company paid Robbie Williams and his wife Ayda an eye-watering £10 million to join The X Factor.

He was convinced the pair would shake up the show. But this month, Robbie announced he won’t be returning for another series.

Was Robbie, I ask, a dud investment? An expensive mistake?

‘Absolutely not. He’s one of the best people I’ve ever worked with, and he’s become one of my best friends. We were on holiday together recently.’

There are plans, he says, for them to work together again, but not in the same capacity. Is there a grand plan, then?

‘Yes, I’m thinking about it when I sit stroking my white cat, making my evil plans for world domination,’ he jokes, sending himself up.

‘No, the truth is that as far as The X Factor is involved, I’m thinking more about the contestants now, rather than the judges. The focus is on the contestants.’

X Factor judges? I should just hire myself!

Frankly, the judges sound like too much hard work. All that bickering with Sharon and Louis.

And the expense of paying them all! ‘Quite,’ he says. ‘I should just hire myself and leave it at that.’

We soon get back to the subject of Eric, and how Simon is keeping his little feet on the ground.

Does his son even know they’re rich? ‘No, I don’t think so. He’s too young to realise.’

How to prevent him turning into the ultimate rich kid? ‘Well, it’s a challenge, but I do want him to have the type of childhood I had, and the same values.

‘You can’t force things, though. I have heard that some people make a big fuss of sitting their kids in economy while they stay in first class, to teach them the value of it. I don’t think Eric could care less, but we quite like having him there to talk to.’

What are the chances of him buying Eric a Ferrari at the age of 17?

He practically goes into orbit. ‘Absolutely not, no way, there’s zero chance of that kind of nonsense,’ Simon says.

‘He might get a Tesla, but I certainly don’t want him to become one of those kids you see on Instagram who have everything and are already jaded by it all.

‘I don’t want Eric to be that person. I’ll tell him, “You can enjoy it when you’ve earned it.”’

Try the Repayment Calculator at barclaycard.co.uk. Britain’s Got Talent, tonight, 8pm, ITV.