Italy’s Giorgio Armani celebrated 40 years in fashion with a star-studded gala and opening of a museum dedicated to his designer business.

The 80-year-old designer, known for his clean-cut and elegant collections, was joined by celebrities such as Leonardo DiCaprio, Cate Blanchett, Hilary Swank and Tina Turner for the bash in Milan, headquarters to his fashion empire.

Nicknamed King Giorgio, the designer, who once worked as a window dresser, is known for being hands-on in creating one of the most recognised fashion brands in the world.

“There have been many moments, from the beginning until today,” Armani told reporters upon arrival at the gala on Thursday evening.

“Maybe my most emotional moment was when I saw my cover on Time,” he added referring to the magazine.

Sophia Loren. Right: Indian actress Aishwarya Rai at Giorgio Armani’s fashion show to celebrate the 40th anniversary of his career and to mark the opening of the Expo 2015 in Milan. Photos: Alessandro Garofalo/Reuters

Armani, who designs both couture and ready-to-wear, has dressed celebrities, royals as well as sportsmen. Stars such as Beyoncé, David Beckham and Megan Fox have modelled his perfumes or underwear.

Maybe my most emotional moment was when I saw my cover on Time

“Madison Avenue in 1985, I think it was, so not very long after he came to our country and I have a closetful still of those beautiful suits, those classic suits, and I still wear them,” actress Glenn Close said of when she bought her first Armani piece.

James Bond actor Pierce Brosnan paid tribute to the stylist, calling him “a mighty man” while Italian actress Sophia Loren simply said the designer “is my friend”.

For the anniversary, Armani has converted a 1950s building that once stored cereals for a new exhibition dedicated to his designs.

The event took place ahead of yesterday’s opening of Milan Expo, of which Armani is special ambassador for fashion.

Officials are counting on some 20 million people visiting the six-month exhibition of worldwide products and technologies.

From left: Cate Blanchett, Leonardo DiCaprio and Hilary Swank.