Prince Albert and Princess Charlene of Monaco both wear elegant blazer and trousers combinations as they take to the stage with their son Prince Jacques, 9, at the Monte Carlo Tennis Masters

They are a famously athletic couple who have both represented their countries at the Olympics.

It's no wonder that Prince Albert and Princess Charlene of Monaco were keen to spend Sunday playing tennis as they took part in the Monte Carlo Tennis Masters tournament.

The royal couple put on a united front, opting for matching suit ensembles as they stepped out with their nine-year-old son Prince Jacques. It is unclear why the child's twin sister, Princess Gabriella, did not attend the event.

In a stylish moment, the family were photographed wearing stylish sunglasses as they watched the action between Norway's Casper Ruud and Greece's Stefanos Tsitsipas in the final at the Monte Carlo Country Club.

Mother-of-two Charlene, 46, a former Olympic swimmer, looked typically chic, wearing a double-breasted navy blazer with white trousers and a light blue shirt.

Albert, who competed in bobsledding at the Winter Olympics five times from 1988 to 2002, demonstrated a similar combination.

The 66-year-old royal opted for a chic black blazer with gray trousers and a striped tie. His son looked equally dapper in a white shirt, black jacket and cream tailored trousers.

It is not the first time that the sporting royal couple has taken part in the tournament – the proud parents were also joined by the two twins last year.

Her appearance at the game comes after reports that Prince Rainier III. of Monaco had begun drawing up plans before his death to remove his son Prince Albert from the line of succession to the throne in favor of Princess Caroline.

The former prime minister of Monaco, who died in 2005 at the age of 81, sought legal advice in the late 1990s about how the succession would proceed if the heir to the throne, Prince Albert, was passed over in favor of his older sister, Princess Caroline.

French newspaper Le Monde reports that Claude Palmero, who was in charge of the palace's finances for more than two decades until he was deposed last summer, confirmed rumors that Prince Rainier was considering changing succession laws in the years before his death.

The report cites a 2001 letter from Patrice Davost, Monaco's head of justice, to Prince Rainier, which confirmed the contents of a meeting to discuss how the Grimaldi name could continue in the royal bloodline, if Princess Caroline's son was Andrea Casiraghi eventually ascended the throne.

According to the newspaper, Mr. Davost's letter addressed to Prince Rainier reads: “I have shared with you my research and thoughts on the following question that was put to me: How to ensure the continuity of the Grimaldi dynasty, its name and its coat of arms?” “Weapons in the event of your grandson Andreas' accession to the throne after Princess Caroline renounced her rights to the crown?”

The report also said Rainier had concerns that his son was “not up to the task” of becoming prime minister and often publicly “belittled” him, causing Albert to stutter when he spoke French.

Mr Davost told Le Monde that he had actually carried out a “discreet” investigation into whether Andrea could one day be crowned Monegasque prime minister – but claimed that Rainier had told him that this was done in the event that Albert died.

The story, which Tatler said Prince Albert dismissed as “nonsense,” is also told in Claude Palmero's notebooks, which the newspaper published at the end of January. The newspaper claims that Mr Palmero has confirmed that Prince Rainier is considering changing the inheritance law in Monaco in favor of Princess Caroline.

The “secret notebooks” of Mr Palmero, who was in charge of the Monegasque palace's finances for more than 20 years until he was unceremoniously deposed by Prince Albert last summer, were published in a Le Monde dossier and contained startling claims about the Monegasque King finances of the family.

In addition to the explosive allegations about the question of succession, the entries detailed outrageous spending by Prince Albert's wife Princess Charlene, who has a general spending allowance of more than £1 million a year.

Speaking to Tatler, one of the journalists who broke the story revealed that Charlene has a “crazy desire to spend money” that her husband grants her to keep the peace.

Gérard Davet, an investigative reporter at Le Monde, said: “Prince Albert says yes to everything.” Charlene is very lonely in the palace; So your best friend may be the prince's money.

He added that the only person who had ever influenced Charlene's spending was Mr Palermo, who filed several lawsuits against Prince Albert following his ouster last year, including for defamation and unfair dismissal.

After Mr. Palermo was escorted from his office by a colonel working at the palace and handed his severance letter, the prince publicly accused his loyal ally of more than 20 years of corruption – which Mr. Palermo flatly denies.

Of Albert's dealings with Palermo, an unnamed journalist in Monaco said: “Albert is a weak person… I think his heart is in the right place, but he avoids confrontation.”

They speculated that the prince's mood was due to having experienced “many” confrontations during the lifetime of his late father, Prince Rainier III.

FEMAIL has contacted the Monegasque palace for comment.

Among the explosive claims uncovered in the dossier were claims that Princess Charlene hired illegal immigrants to work for her for less than £90 a day, despite her personal allowance rising to £1 million a year.

Mr Palermo's documents revealed that a large proportion of Charlene's eight-strong full-time staff were made up of “illegal migrants” – something the accountant raised concerns about.

“Your Serene Highness the Princess allows people to work for her who do not comply,” Mr. Palmero warned Prince Albert, also referring to “a part-time Filipino woman who ties dogs in the shower.”

In a January 2017 letter, he said another employee from the Philippines had been “illegal for five years” despite only having a one-month tourist visa.

“He gets 100 euros a day.” [£85] This is off scale,” Mr. Palmero wrote.

In December 2014, Charlene gave birth to Prince Jacques and Princess Gabriella and immediately placed them in the care of illegal immigrant nannies.

“Update on hiring nannies… We are completely illegal (even her tourist visa expired on January 7th),” Mr. Palmero wrote on January 15th of the same year.

“Not only are they in an illegal situation, they also entered with a false passport,” Mr Palmero added.

Despite this, Mr Palmero released almost £600,000 to celebrate the children's birth and christening.

In one day alone in April 2016, Charlene demanded the equivalent of £66,000 and that was “definitely too much”, said Mr Palmero, especially as she also planned to rent a second villa in Corsica.

“Isn’t that a lot?” asked the accountant, worried that the princess was taking money from “undeclared” funds for tax purposes.

“These practices are dangerous,” Mr. Palmero warned.

“Not only are they in an illegal situation, they also entered with a false passport,” Mr Palmero added.

The former top royal wealth manager in the Mediterranean tax haven claims he desperately tried to curb Charlene's “dangerous” spending and at one point blocked the South African-born 45-year-old from hiring new staff.

The books also claim Albert spends millions every year from a secret French bank account to pay his former lovers and children – with Jazmin Grimaldi, 31, and Alexandre Coste-Grimaldi, 20, each receiving £344,000 a year.

At this point, Charlene invested £826,000 renovating her holiday villa in Calvi on the island of Corsica and £860,000 decorating her office in Monte Carlo.

Charlene paid her personal chef the equivalent of £250 a day from petty cash, Mr Palmero said, while her South African family also received hundreds of thousands of pounds.

In February 2017, the accountant also released the equivalent of more than half a million pounds to pay off the princess's overdraft.

In December 2019, an alarmed Mr Palmero noted that Charlene had spent “around 15 million euros”. [£13m]', over eight years, even though her pocket money was '7.5 million euros' [£6.4m]

At this point, Charlene invested a total of almost £2 million on the holiday villa in Calvi and the renovation of her office.

'It's crazy!' Mr. Palmero wrote. “I have no control over the princess’s spending.”