People often complain that footballers get paid too much.

And while the Range Rovers, mansions and Rolex watches might be affordable for most Premier League players, they would have nothing on this man, if things go his way.

Yep, you may not have realised but Arsenal midfielder Mathieu Flamini could be set to become a billionaire in the near future.

Mind you, no-one knew about his secret money-making plot – not even his family and close friends.

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So what’s the plan?

In the past few years the 31-year-old has spent millions on research, trials and made major scientific breakthroughs in the energy field.

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This week his company, GF Biochemicals, announced that they had become the first company in the world that can mass produce Levulinic Acid – which can replace oil.

Flamini employs around 80 people in the plant of his company GF Biochemicals in Caserta, with around 400 workers making a living thanks to the Frenchman and his business partner Pasquale Granata.

So how’s he making the money?

As you’ll know, oil is big business. It basically pays for Raheem Sterling’s wages.

So replacing the non-renewable source with Levulinic Acid could be revolutionary – and the industry is already thought to be worth £20billion.

Flamini, in an exclusive interview with SunSport this week, takes up the story.

“For seven years I haven’t mentioned it to anyone. When I moved to Milan in 2008 I met Pasquale, who became a close friend and we always had in mind to do something together.

“I was always close to nature and concerned about environmental issues, climate change and global warming.

“He was on the same wavelength. We were looking how we could make a contribution to the problem.

“After a while we found out about Levulinic Acid. It’s a molecule identified by the US Department of Energy as one of the 12 molecules with the potential to replace petrol in all its forms.”

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Flamini may not be one of the game’s greatest pioneers, but his company could be on the cusp of an energy revolution.

He added: “A football career is made of ups and downs. To me, it was an escape.

“It cleared my mind and helped me to think about something different. And it was something intellectually challenging too.”

“Pasquale and I still ask — why us? So many people have tried and failed before so why did we succeed?

“But it’s about believing. I read up on chemistry. I am not a chemist, I started my law studies at Marseille University until I had to give up because of my football career.

“But I know a lot about LA and the process of course.”

It might just be us, but you just can’t see Harry Kane talking like this, can you?

Flamini added: “Researchers told us LA is the future and by doing research in that field we could come up with a great discovery and success.

“We financed the research by the Milan Polytechnic.

“After several months we came up with the technology of how to produce LA on an industrial scale, meaning cheaply and cost-effectively. We patented it.”

Perhaps the most incredible part of the story is that Flamini managed to keep it all a secret.

He continued: “I was not thinking about losing millions. When I started I knew it would happen but of course there are times when you doubt.

“Not even my family knew anything about it. My parents did not know about it until about a year ago.

“First, they were worried, but now they are proud. My Milan team-mates probably found out in our launch this week and my Arsenal teammates will probably find out reading this.

“I don’t think Arsene Wenger knows, I never spoke to him about it. I wanted it to be all in place first, up and running and announce it when I was ready.

“We’ve come here after seven years of work. We achieved something that has never been done before. Of that I am the most proud.”

We have a feeling Flamini may just make a few more friends in the next couple of years.