It was the move of the summer.

After months of speculation, Kylian Mbappe joined Real Madrid on a free transfer after finishing his contract at Paris St-Germain.

He has signed a deal until 2029, earning £12.8m a season, plus a £128m signing-on bonus to be paid over five years, and he will keep a percentage of his image rights.

With the ink dry, one could be forgiven for thinking the only thing left for Mbappe to prove is that he is the finest player in the world at the biggest football club on the planet.

But things are never quite that simple as he prepares for his first Champions League match with his new club - Tuesday's home game against Stuttgart.

How will Mbappe fit into the European champions' line-up, whose star-studded attack already boasts Vinicius Junior, Rodrygo, Jude Bellingham and Brazil youngster Endrick?

While back in his native France, Mbappe is battling against his former club PSG over financial issues and facing mounting criticism from supporters of the national side.

Real Madrid insiders have been surprised by the humility, attitude and absence of diva traits Mbappe has shown since his arrival - although it has not surprised those who know him best.

He has adapted well to whatever has been put in front of him, despite perhaps not having been so accommodating in the past.

As an 18-year-old at PSG under manager Unai Emery, he told the club not only that he had to play every game but also where he had to play, which most certainly was not as a number nine.

When Luis Enrique played him as a number nine he could not deal with it.

Now with Real Madrid he plays as a number nine, having fewer touches of the ball and being less involved.

Manager Carlo Ancelotti has given him licence to move as he wishes, but when he moves towards the left he ends up clashing with Vinicius, who has as great - if not greater - reluctance to play as a number nine as Mbappe.

But that is not Ancelotti's only problem.

Without the retired Toni Kroos in the line-up there is no fluidity to the football of Real Madrid. This makes it difficult for the forwards, who are not able to rely on the invaluable support of their team-mates as they have in the past.

With Vinicius not in the greatest form, Mbappe cut a frustrated figure in his first few matches for Madrid with his runs not being spotted by those around him.

He has still scored four goals in six games, although two have come from the penalty spot. Initially he was not scoring as he would have liked, including going three games without a goal - but only a section of the media put him under pressure.

In big games Ancelotti will almost certainly play Vinicius, Mbappe and Rodrygo. But often, like Saturday's 2-0 win at Real Sociedad, it will be in a 4-4-2, so Vinicius and Mbappe can decide among themselves what to do and who goes where.

One problem Ancelotti most certainly has not got is Mbappe's attitude, which has been exemplary.

Someone at the club told me recently: "Do we really need to adapt Mbappe to the club? We don't need to because he is the best player in the world."

And they added that "the biggest surprise is how little of a superstar he assumes himself to be".

Speaking to journalists after scoring twice against Real Betis, Mbappe said: "It is me who has to adapt. When a player like me arrives, many things change and it would be crazy if I didn't think so and overcome that."

In their 2-0 win against Real Betis at the start of the month, Vinicius gave way to Mbappe on penalty-taking duties. Against Real Sociedad they took one each.

Ancelotti has said the players can sort it out between themselves, and Mbappe is happy with that because he believes he is at a club which will reinforce his value and skills.

He believes he must remain patient and that he will eventually take all the penalties and Vinicius will adapt to him.

Mbappe realises there is currently a protocol he has to accept. He is convinced the team will work around his immense talent soon enough, though.

Nothing leaks out of the Real Madrid dressing room without the blessing of the club's powers that be.

And suddenly we are beginning to see a trickle of stories emerge, criticising the attitude of Vinicius and his constant battles on so many fronts.

The message is clear that, as far as the club is concerned, if anyone had to leave it would be Vinicius - albeit for a huge sum of money.

There are other consequences to the arrival of Mbappe.

It has left Rodrygo feeling a little pushed aside, on and off the pitch. Real are also going to have to identify what role Bellingham will play in this environment on his imminent return from injury.

Commercially, Mbappe is everywhere. He has kept 80% of his commercial rights, although that figure varies according to which part of the world the club are looking to sell their products to.

Last weekend's match against Real Sociedad was the first of seven games they face in 21 days - five in La Liga and two in the Champions League.

What we saw was a fresh Mbappe - although clearly not at his peak. He moved all over the front line, made more runs with the ball than in any other game, dropped deeper and was more involved.

Vinicius and Mbappe did not pass to each other much in the first matches of the season, but it was the biggest connection on the pitch at the weekend.

And - as far as the club are concerned - while it might take a little longer to put Mbappe in the category of best in the world, everyone believes it is only a matter of time before he becomes the main star at the world's biggest club.

There are currently two Kylian Mbappes in circulation.

One aiming to establish himself in Madrid, and the other still battling his former club Paris St-Germain, following an acrimonious divorce and struggling to maintain the respect of the France national team he has represented with such distinction.

It would be disingenuous to imagine his problems with PSG and France are not in some way linked.

Things came to a head recently when France were convincingly beaten at home in a Nations League match against Italy.

After the 3-1 defeat, France goalkeeper Mike Maignan launched a blistering attack against the whole team, including, without naming any names, the so-called stars (Mbappe and Antoine Griezmann) who averted their gaze as he lambasted them for a lack of desire and aggression.

L'Equipe, an organisation about as powerful as sports media can be in France, has suggested Mbappe is currently disconnected from the France team.

Hours before the game against Belgium, Mbappe told the media he believed the side needed better tactical work to allow players to adapt to what the coach requires, which many saw as a thinly-veiled criticism of manager Didier Deschamps.

He was, as it had always been planned, a substitute for the next game against Belgium.

It is important to note, while doing the business for both his former club and country, he was untouchable - beyond reproach.

The symbol of the city of Paris, a national hero for having stayed at PSG until the Olympic Games, something he did after receiving a lot of pressure from everyone, including President Emmanuel Macron.

Since departing France it has been open season towards the player from the fans, the media and specifically the club who have about 46 million reasons for wanting to increase the animosity against their former golden boy - Mbappe insists PSG owe him £46m in back wages and promised bonus payments.

The club disagree, claiming he waived the money in exchange for being included in the squad he had been ejected from before PSG's pre-season tour of Japan last summer.

The league has now ruled in favour of the player and ordered the club to pay him the money, which PSG will appeal against.

Mbappe will be glad to concentrate on his football.