Simpson Thacher & Bartlett and Chiomenti Studio Legale have bagged the leading roles advising on Versace's sale of a 20% stake to US private equity house Blackstone.

The sale of the €210m (£172m) stake values the family controlled Italian fashion house at around €1bn (£821m).

Simpson Thacher advised longstanding client Blackstone on the deal with a team led by City corporate partner Mike Wolfson. Italian firm Gianni Origoni Grippo Cappelli provided local law advice, fielding corporate and M&A partners Francesco Gianni and Ilaria Placco.

Versace was represented by Italian firm Chiomenti Studio Legale, which fielded a team including corporate partners Michele Carpinelli and Simone de la Gatinais. Milan firm Gattai Minoli & Partners also acted for the iconic design brand, with name partner Bruno Gattai leading.

Versace group creative director Donatella Versace said in a statement: "We have gained a strong and unique positioning in luxury fashion, and I believe that this investment in the company, together with our clear direction and our outstanding management team, will enable us to achieve Versace's potential."

In exchange for the stake Blackstone will inject €150m (£123m) of fresh capital into the company and will acquire €60m (£49m) in stock from family holding company GIVI Holding.

The proceeds will be used to fund new retail stores and develop Versace's brand portfolio, product offering and e-commerce business.

Simpson Thacher is a regular adviser to Blackstone, notably acting for the private equity house on hotel operator Hilton Worldwide's plans for an initial public offering, which emerged last September.

Last October Wolfson led a team of lawyers advising Blackstone in relation to the $1.65bn sale of Mivisa Envases to Crown Holdings.

However, while Blackstone counts Simpson Thacher as its principal adviser globally, it is increasing the number of firms it works with in London and Europe.

Related: Simpson Thacher-Blackstone ties loosen as PE house shops around