The Royal cash machines? PR experts predict Prince Harry and Meghan Markle could become world's highest-earning celebrity couple

Prince Harry and Meghan, Duchess of Sussex, could soon be cashing in.

Harry and Meghan could become the world's highest-earning celebrity couple – with riches stretching to a billion dollars within a decade, PR experts predicted yesterday.

As superstars of the international circuit, they would be able to command six or even seven-figure fees just for turning up at an event.

If they decide to keep their royal titles while touting themselves for hire, their combined money-spinning potential could be greater than any A-lister in history.

Experts said becoming a brand ambassador for a global giant such as Google or Apple could earn the couple tens of millions annually. A nine-figure sum each year – $100million – would add up to $1billion (£760million) over a decade.

The couple have yet to say exactly how they will meet their ambition to 'become financially independent'. But their unique stellar cachet – blending blue blood and Hollywood royalty – could net them huge amounts.

Ronn Torossian, of New York PR firm 5W Public Relations, said: 'Their earning power – both individually and as a couple – is limitless in all aspects of endorsements.

'Whether appearances, brand partnerships or more, they could make eight or nine figures annually with endorsement deals.'

Mr Torossian added: 'The sky is the limit for the two of them.' Until now, Harry's senior royal status has prevented him from making money from his celebrity. He and Meghan have complained on their new website that they are 'prohibited from earning any income'. As with all the royals, the precise details of how they fund their lavish lifestyles are kept opaque. But some sources of the Duke and Duchess of Sussex's wealth are known.

Harry and William share a handout from Prince Charles's Duchy of Cornwall estate, which last year came to £4.9million for both princes. Harry's proportion is unknown but thought likely to be about £2million. He and Meghan have said this accounts for 95 per cent of their 'office expenditure'.

The remaining five per cent, they said, comes from the Sovereign Grant – in other words, the British taxpayer. If so, this would suggest they receive about £100,000 from the public purse to support their office costs.

The couple said on their website: 'Their Royal Highnesses prefer to release this financial tie.' However, no mention was made of the millions from Charles. Asked whether Harry hoped to cling on to this revenue stream, a Palace insider made clear it was an issue that had not even been discussed by the Royal Family yet. Continuing to take money from the £1.2billion Duchy of Cornwall estate – which owns property swathes of land in the West Country and the Oval cricket ground in London – would be controversial as Charles only has it because he is the Queen's heir and some say it should be regarded as a public and not a private asset.

Harry and Meghan's 'office expenditure' is by no means the whole story of their wealth. It is not stated who pays for their six-week holidays, the new designer kitchen at their Frogmore Cottage home in Windsor and other luxuries. Other sources of income include Harry's inheritance from his mother Princess Diana.

In her will, she left £21million to her two sons, to be held in trust until they turned 25. In the intervening years, the fund was overseen by the chairman of Coutts Bank and will have grown significantly. Estimates put Harry's portion at up to £20million.

Happier times for the family.

The Duke of Sussex also received an estimated £7million from the Queen Mother, who in 1994 put two-thirds of her £70million fortune into a trust fund for her great-grandchildren.

Harry's portion could be even higher because the Queen Mother reportedly thought he should get more than William to make up for not being king. That is before interest payments, which could easily have doubled the windfall before Harry was given access to it.

Over his ten years in the Army, Harry would have been paid a total of around £450,000. Overall, his 'net worth' has been estimated at about £30million. His wife's wealth has been put at £4million. Her biggest earnings before becoming a royal were from her role in the TV drama Suits, which paid her £2million over seven years.

She made six-figure sums for various film roles and about £60,000 a year endorsing products while running her lifestyle blog, The Tig. She also owns property in Toronto. But all this could be small-fry compared with the global money-spinning opportunities that lie ahead. PR guru Mark Borkowski, who has worked with TV stars Noel Edmonds and Graham Norton, said: 'They will make a fortune. I think around the world people will be falling over to get brand connections with them.'

Retail expert Andy Barr predicted the couple's 'Sussex Royal' brand could rapidly become worth almost half a billion pounds.'

He added: 'As the brand they are building will automatically have global appeal, their revenue will grow even further.' PR professional James Henderson, who used to run Bell Pottinger and previously advised Madonna and Naomi Campbell, said: 'She [Meghan] could endorse products and have her own beauty brand, they could start a TV channel in the States to raise awareness of their causes – the possibilities are endless.

Meghan, Duchess of Sussex and Prince Harry, Duke of Sussex

'Meghan is a beautiful, talented and articulate woman. Appearance fees could easily be $100,000 just for turning up to an event, without actually having to do anything else.' The world's current highest-earning celebrities, the Kardashian family, are estimated to have a net worth of $1billion. Harry and Meghan have already quietly trademarked their Sussex Royal brand on more than 100 items, including pencils, socks, bookmarks and even hoodies.

Given their philanthropic ambitions, the couple may well decide to follow in the footsteps of former US presidents. Barack and Michelle Obama set up a charitable foundation and produced documentaries to promote their causes, while also cashing in with lucrative public speaking opportunities, books and TV deals.

Harry and Meghan have plenty of A-list friends who are as business savvy as they are famous to help them transition into their new lives – and make money along the way.

Last year, Meghan secretly invited Hillary Clinton to Frogmore Cottage to meet her baby son Archie. Oprah Winfrey recently teamed up with Harry to create a mental health documentary series after attending the couple's wedding in 2018. If Harry and Meghan choose to write memoirs about their lives, they would start a spectacular bidding war between publishing houses and procure eight-figure advances. Fans would love to read about their vastly different childhoods and how their lives became entwined. In 2017, the Obamas scored a joint book deal at Penguin Random House worth a reported £49million.

The duke and duchess are both activists in their own right, so it is not hard to imagine them getting into film and television production to raise awareness for causes.

They could also earn megabucks on the public speaking circuit. Mr Obama, Bill Clinton, George W Bush and Tony Blair all command six-figure speaking fees.

Jeff Jacobson, of the Talent Bureau speaking agency, predicted the Sussexes would get at least $100,000 (£75,000) per public appearance, while Harry could receive up to $500,000 (£382,000).

However, among the costs racked up by the couple will be for their police protection officers – well over £1million a year, funded by British taxpayers. Yesterday an employment website calculated that if Harry and Meghan were ordinary jobseekers, based on their skillsets, education and work experience, they would earn £40,684 in his case and £139,685 in hers.