A traditional waltz? A modern Belgian tune? Neither - the choice was Eric Clapton's "Wonderful Tonight". It was left to Raymond van het Groenenwoud, the musical arranger, to explain such a quintessentially Belgian compromise. "It couldn't be either a Dutch-language or a French number," he said.
It is a measure of the bitterness between Belgium's two communities that this Saturday's royal wedding has been dragged into the linguistic divide it was hoped the event might bridge. Philippe and his bride have had their party spoiled by a rash of media revelations. The result has been a fierce debate about intrusive journalism and a new bout of recrimination between the Dutch-speaking Flemings and the French-speaking Walloons.
All of which has come as something of a shock. In Belgium the monarchy is afforded the kind of respect which prevailed in Britain before the age of divorces, tabloid revelations and It's a Knockout. This reverence has endured into the 1990s precisely because of royalty's role in glueing together a fractious nation. Electing a president would be so divisive that the royal family has become an uncontentious element of the modern-day state.
Hence the celebrations when, in late September, the engagement was announced on the lawns of the palace at Laekan, just outside Brussels. Tall, fair- haired and mildly foppish, Prince Philippe has had difficulty winning the affections of the Belgian nation. "Le Prince Triste" may not have a reputation for talking to his plants, but he was unceremoniously passed over in 1993, when King Baudouin died and the throne passed to the late king's brother, Albert II. Belgians had long speculated about the failure of Philippe, 39, to find a bride until, in September, the prince emerged with the ideal candidate - so good, in fact, that Philippe angrily denied suggestions that this was an arranged marriage.
Not only is Mathilde d'Udekem d'Acoz aristocratic and glamorous, but she is Belgian, marking her out as a rarity among royal brides. In fact, she is destined to be the first home-born queen in the country's history. Perhaps more significant, Mathilde has the credentials to act as a binding force between the French and Flemish communities. Her father comes from a line of Flanders-based nobility, but the family chateau is in Wallonia at Villes-la-Bonne-Eau, near Bastogne. Although francophone, she also speaks Dutch; just how fluently is a matter of debate, but a command of the language is an important factor when powerful forces in Flanders are pressing to break from Wallonia.
It would be an exaggeration to say that the notoriously down-to-earth Belgians were gripped by euphoria, but slowly pictures of the couple began to go up in bakeries, schools and newsagents around the capital. Generale Bank announced it was minting commemorative coins, the press gushed about the design of the wedding dress, and the wedding date of 4 December was declared a day of free transport in Brussels.
The sleek and charming Mathilde was an instant hit, emblazoned on a host of magazine covers, and the parallels with Diana, Princess of Wales were quickly drawn. Even Philippe's stock rose as he was trailed by camera crews around formal functions.
Enter Mario Danneels, a teenage student whose book on Queen Paola dropped a bombshell by making public the claim that King Albert has an illegitimate daughter, Delphine Boel, 31, an artist now living in London. Dismissed as "tittle-tattle" (but not denied) by the palace, the claims were ignored or disbelieved by many, according to opinion polls. But they came just as Philippe and Mathilde began a pre-nuptial tour of Belgium, the so-called Joyeuse Entree or Blijde Intreden, which had been carefully choreographed to take in French and Dutch-speaking areas in equal measure.
Le Soir, the French-language daily, initially hid the claims on page 16, but soon its rival La Libre Belgique was proclaiming on page one: "Climate of media controversy for the first Joyeuse Entree". Inside coverage included a discussion on the "tabloidisation" of the Belgian press.
Recriminations swiftly followed. While still popular in Flanders, the monarchy is regarded as an obstacle by hardline separatists there who want to break away from the poorer south. In a television debate, one speaker attacked Mr Danneels's book as a Flemish plot against Belgian unity, which was being reinforced by the royal engagement. The author himself had to deny that the anti-monarchist, extreme-right Vlaams Blok were behind his book.
Tensions have been further heightened over a new set of claims that the country's youngest prince, Laurent, is not the natural son of King Albert. Ignored by the French press, these claims were picked up by one Dutch-language paper, Het Nieuwsblad, under the less than subtle headline "Laurent is een bastaardzoon".
Philippe and Mathilde have kept the show on the road during their national tour, despite Flemish separatist demonstrations organised by students, which led on one occasion to 16 arrests. Similar trouble is unlikely on Saturday, if only because security will be tight.
When I asked the official spokesmen for the Vlaams Blok if he would be watching the big event on TV, he snorted that he had "better things to do". The appeal of the monarchy, he argued, was only as deep as the "fairytale atmosphere created by the press", and will fade after the event.
Even for the glamorous female candidate, marrying into royalty in Belgium may be little easier than it is in Britain.