Fashion house Chanel has made its first wine acquisition outside France, buying Napa Valley producer St Supéry from the Skalli family for an undisclosed sum.

Chanel owners Alain and Gérard Wertheimer – who have an estimated fortune of €16.6bn – will add the St Supéry winery and its 200-plus hectares of vineyards to their two Bordeaux properties, Château Rauzan-Ségla and Château Canon.

Skalli said he was ‘delighted’ to sell St-Supéry Estate Vineyards & Winery to Chanel, which he said understood luxury brands and would ‘continue to enhance this special property’.

Napa Valley is home to the most expensive vineyard land in California and recent figures suggest there is growing collector interest California Cabernet.

‘I am confident that they will continue my vision of a Napa Valley château, crafting world-class estate wines, and will build on that foundation, ever improving quality,’ Skalli added.

St Supéry was established in 1985, three years after Skalli bought over 1,500 acres of land in Napa Valley, and has become a specialist in Cabernet Sauvignon and Sauvignon Blanc, all made from its own vineyards.

The sale comes four years after Skalli sold Skalli Wines’ brands, vineyards and facilities in Provence and the Rhône Valley to rival producer Boisset, including the Caves St-Pierre, Couleurs du Sud and Fortant de France brands.

Robert Skalli had taken over the family wine business at the age of 22 in 1972, eight years after his father Francis Skalli died in a plane crash at the age of 39.

Inspired by the example of Robert Mondavi, he went on to expand the business with acquisitions and the creation of Fortant de France, described by some as France’s first true wine brand.

The Wertheimers, brothers whose €16.6bn fortune makes them the seventh-richest people in France, already own two Bordeaux châteaux, Margaux second growth Rauzan-Ségla and St-Emilion classed growth Canon.