Eden Hazard assimilated himself into Lille's youth setup so smoothly that some of his team-mates did not even realise he was from Belgium.
"We were all French in the group and he was always hanging around with us. I thought he was French," Yannis Salibur, Hazard's former Lille team-mate, told L'Equipe this week.
"I only found out he was Belgian when he said 'nonante' [the Belgian French word for 'ninety']."
Hazard joined Lille's academy at the age of 14, with his decision strongly influenced by the fact that his family home in the Belgian town of Braine-le-Comte, 20 miles south-west of Brussels, would be just a short hop across the border.
As a youngster, Hazard adored Zinedine Zidane and would later describe him as his "idol." A photograph from a TF1 documentary resurfaced recently that shows a cherubic Hazard and younger brothers Thorgan and Kylian wearing "ZIDANE 10" France shirts during a holiday in France in the early 2000s.
The seven years that Hazard spent at Lille, where he won a Ligue 1 and Coupe de France double in 2011, gave him a profound attachment to Zidane's country.
"He blended in perfectly with the culture of northern France and the northern traditions," Francois Vitali, Lille's former head of youth development, tells Bleacher Report.
"He became 'Frenchified', of course, because he came to France, but more than that, he became 'northernised,' in terms of the local customs, his way of being and his way of behaving with other people."
In a press conference ahead of Belgium's World Cup semi-final against France on Tuesday, Hazard's Chelsea team-mate, Olivier Giroud, described him as "almost a Frenchman." Though he is now Belgium captain, Hazard has previously admitted that he knows the words to the French national anthem, " La Marseillaise," better than those of its Belgian equivalent, "La Brabanconne." But he has also been very clear that the option of playing for France was never on the table.
"It never crossed his mind to play for France," says Vitali, who now works as the sporting director of Belgian club Cercle Brugge.
"His parents chose to send him to Lille because he'd get a good [football] education, not because he might become French one day and wear the colours of the French team. For them, and for him, he's Belgian, he's proud to be Belgian and he'll be very happy to play against France."
Hazard will not only be one of the chief threats facing France in Saint Petersburg. He is also a symbol of the multiple bonds connecting the two squads that make Tuesday's game (9 p.m. local, 7 p.m. BST, 2 p.m. ET) the most incestuous semi-final in World Cup history.
Prior to kick-off at Krestovsky Stadium, you can expect to see Hazard catching up with France's wisecracking centre-back Adil Rami, with whom he spent four years at Lille.
Hazard's younger brother, Thorgan, might be spotted having a word with Raphael Varane, with the pair having played together in the youth team at Lens. Belgium striker Michy Batshuayi is sure to have a joke for Steve Mandanda, Benjamin Mendy and Florian Thauvin, who were his team-mates during his two-year stint at Marseille.
Were Thomas Meunier not suspended for Tuesday's game, he would be marking his former Paris Saint-Germain team-mate Blaise Matuidi.
There are also multiple club connections, many of which have been forged in England. Hazard, Batshuayi and Thibaut Courtois play alongside Giroud and N'Golo Kante at Chelsea. Toby Alderweireld, Jan Vertonghen and Mousa Dembele are Tottenham club-mates of France goalkeeper Hugo Lloris. Romelu Lukaku and Marouane Fellaini play with Paul Pogba at Manchester United. Lukaku and Pogba have been on holiday together, while Adnan Januzaj, who came through the United youth ranks with Pogba, has described France's No. 6 as "a brother."
The members of Roberto Martinez's Belgium squad who have played football in France were walking a well-worn path. Countless Belgian footballers have made careers for themselves on the other side of the border, from Robert De Veen, who starred up front for Lille and Lens in the interwar years, to the great Enzo Scifo, who played for Bordeaux and Auxerre and won the Ligue 1 title with Monaco in 1997.
It was a Belgian, meanwhile, who masterminded France's first—and, to date, only—triumph in the European Cup. Raymond Goethals was in charge of the Marseille dugout when Basile Boli's glancing header brought the French side a 1-0 victory over AC Milan in Munich in 1993.
The French and the Belgians share much more than a border, a language and a passion for cycling. That means that despite its global importance, Tuesday's match will have a distinctly local flavour. L'Equipe says that it is like "going on a faraway trip, stumbling across a beach paradise and finding a guy from the office lying there on a towel."
For decades, Belgians have been the butt of French jokes, chiefly on account of the differences between the French spoken in France and the clipped, nasal French spoken in the French-speaking parts of Belgium. Belgians, for their part, poke fun at France's pretentions towards sophistication in much the same way as the rest of the world does.
"We often find the French pretentious, and the French tend to find us ridiculous, particularly because of our accent," summarised Charles Michel, Belgium's prime minister, in an interview with French newspaper Le Journal de Dimanche.
Gunter Jacob, a Belgian who spent time working in France as sporting director at Marseille, says that views of France in Belgium differ depending on whether you are in French-speaking Wallonia or Dutch-speaking Flanders.
"You have to remember that we have two sides in Belgium: the French-speaking side and the Dutch-speaking side," he says.
"The rivalry from the Dutch-speaking side is with Holland. The rivalry from the French-speaking side is more with France. I'm on the Dutch-speaking side, so you don't get it that much. It's a friendly rivalry."
In football terms, the rivalry between Belgium and France began on May 1, 1904, when the two national teams faced off in a friendly that represented the first official match for both countries. The game took place in front of around 1,500 spectators in Uccle, birthplace of Belgium defenders Vincent Kompany and Dedryck Boyata, and finished in a 3-3 draw.
Belgium won 7-0 when the teams next faced off a year later, with their cause helped by the fact that French goalkeeper Georges Crozier had to leave the field in the 65th minute to catch a train back to his army barracks in Paris. (He arrived late and was sentenced to 15 days in prison.)
The teams played each other in friendlies on an almost annual basis until the late 1960s. A particularly poignant meeting took place on Christmas Eve 1944, when Belgium came to Paris to play the first official match there since the liberation of the French capital four months earlier. All proceeds went to victims of the war.
Tuesday's match will be by far the most important encounter between Belgium and France. Just like today, the two countries produced talented generations of footballers in the mid-1980s, but although they met at successive major tournaments, neither match was a knockout game.
Michel Platini scored a perfect hat-trick—left-foot piledriver, right-foot penalty, header—as France thrashed Belgium 5-0 at Nantes' Stade de la Beaujoire in a group-stage match at the 1984 European Championship, which propelled the host nation into the semi-finals of a tournament that they went on to win.
Diego Maradona's Argentina and Karl-Heinz Rummenigge's West Germany prevented France and Belgium from facing off in the World Cup final in Mexico two years later. The sides met instead in the third-place play-off in Puebla, with France prevailing 4-2 after extra time courtesy of goals from Bernard Genghini and Manuel Amoros.
Despite a much less impressive football pedigree, Belgium hold the upper hand in the rivalry, with 30 wins to France's 24, and there is understandably a feeling in the country that this is a now-or-never moment for the national team.
"It's obvious that they [France] have a list of honours that we don't have yet and will probably never have," says Jacob. "But now we've got a really good chance with a very good generation to maybe go into the final and perhaps win it."
Nobody in the stadium on Tuesday will feel the peculiarities of the occasion more keenly than Thierry Henry, France's all-time record goal-scorer, who will be sitting in the Belgium dugout as one of Martinez's assistants.
Henry, who scored 51 goals in 123 international appearances, is considered to be one of France's greatest ever players, and there is bemusement in France at the thought that he is now plotting the downfall of the national team whose colours he wore for so many years and with such distinction.
"It'll be strange because he's French and he'll be in the opposition dug-out. I think it'll be strange for him too," said France coach Didier Deschamps, who played alongside Henry in the teams that triumphed at the 1998 World Cup and the 2000 European Championship.
For all the success that he enjoyed with France, Henry's international career ended beneath a cloud. His legacy was tarnished by his infamous handball against the Republic of Ireland in November 2009 and his involvement in the catastrophic World Cup campaign that followed it.
Deliberately or not, he has distanced himself from his homeland in the years that have followed, spending four-and-a-half years playing football in the United States and then settling in the United Kingdom, where he completed his coaching badges and launched his career as a television pundit.
Noel Le Graet, president of the French Football Federation, has conceded that his organisation "lost sight" of Henry. Asked once why he had joined the Royal Belgian Football Association and not its French equivalent, Henry replied: "Nobody ever offered me anything."
Henry appears to have struck up a close relationship with Lukaku, upon whom Belgium are relying for the goals that will end France's tournament. It will be one of innumerable curious subplots in a truly singular semi-final.