Long before Wagner coined the term, opera producers had dreamt of creating the complete work, the ultimate art, a Gesamtkunstwerk. In 1644 the diarist John Evelyn described an opera he saw in Rome in which Gian Lorenzo Bernini had “painted the scenes, cut the Statues, invented the engines, composed the Musique, writ the Comedy, and built the Theatre”. And throughout the 18th century flashy impresarios would enhance opera performances with grand, perspectival sets, sophisticated mechanical effects and menageries of birds and animals.

It seems more than coincidence, however, that there has been an increased emphasis on visuals since Wagner penned his ideal. Of course, efforts at cultural enrichment or exchange are not the only reason for showy, multidisciplinary projects; often the motives have been more dubious – épater les bourgeois, crude commercial gain or vainglory. Diaghilev's 1924 opera-ballet Le Train Bleu for the Ballets Russes, popular though it was, just sounds like an elaborate exercise in name-dropping: score by Darius Milhaud, libretto by Jean Cocteau, choreography by Bronislava Nijinska, curtain designs by Pablo Picasso – costumes by Coco Chanel, naturellement.

Since then Salvador Dalí, Luchino Visconti, Henry Moore, David Hockney and Werner Herzog have engaged with opera, but as the cult of the director has gathered pace in recent years, the practice of employing celebrity outsiders is now commonplace among European opera houses. A glance at the programmes confirms the trend: Opéra Bastille have just presented a new work by J?rg Widmann, staged by the German artist Anselm Kiefer, and English National Opera are about to open with Le Grand Macabre, led by the Barcelona theatre troupe La Fura dels Baus. But in this hotbed of hype Théatre de la Monnaie stands out. Their season-opener is a new interpretation of Handel's Semele that will unite the celebrated baroque conductor Christophe Rousset, and his period ensemble Les Talens Lyriques, with the provocative Chinese visual artist Zhang Huan.