Hollywood icon Lauren Hutton joined Gigi Hadid on the catwalk as the world of glamour united across the generations to celebrate 50 years of venerated Italian fashion house Bottega Veneta in Milan on Saturday.

In what was the eagerly anticipated highpoint of the latest round of fashion shows, the Venetian outfit celebrated for its discreet craftsmanship marked the occasion in style in the august surroundings of Milan's historic art school, the Accademia di Brera.

The brand was also celebrating 15 years since Tomas Maier took charge of its artistic direction and the men's and women's collections he created for the occasion were typically imbued with the discreet luxury that is Bottega's trademark.

But as an event this was less about the clothes than who was wearing them -- and it was 72-year-old Hutton who stole the show.

The actress drew gasps of astonishment and bursts of spontaneous applause as she elegantly shimmied round the runway in a sandy-coloured silk trench coat that might have come straight from the costume department of Hollywood's golden era.

Hutton, who clutched the same red leather Bottega purse she carried when she starred alongside Richard Gere in "American Gigolo", later linked arms for an encore alongside Gigi Hadid, the 21-year-old American whose 23-million-strong following on Instagram has made her one of the most powerful players in the fashion industry.

Hadid, who has also walked for Max Mara, Fendi and Moschino during her attention-grabbing visit to the Italian fashion capital, was dressed in a dusty-pink two piece.

Now owned by French conglomerate Kering, which also has Gucci in its stable of luxury brands, Bottega Veneta was founded in 1966 by Michele Taddei and Renzo Zengiaro.

A total of 76 models strutted their stuff around the arched hallways of the Accademia, including Gigi's sister Bella and a supermodel from another era, one-time Wonderbra star Eva Herzigova.