Financial terms of the deal, revealed Monday, were not disclosed.
Management at the Paris-based firm, led by family members, including chief executive officer Laurent Gerbi Darel, creative director Daniele Darel and vice president Gérard Darel, will remain in place.
Darel has been doubling sales every five years for the past 15 years to reach 158 million euros in 2007, or $216.6 million at average exchange rates, and now wants to step up the pace.
"The challenge for Gérard Darel today is to develop our brand internationally, be it through our own stores or with strategic partners outside Europe," Gerbi Darel told WWD. "We needed a strategic and financial partner to support that. To develop rapidly you need critical mass."
With its new backer, the firm plans to double its global presence — which today counts 90 own-brand shops, 140 department store concessions and 1,200 multibrand boutiques in more than 40 countries — in order to boost international revenues to 50 percent of sales from the current 30 percent. To strengthen the brand's global appeal, Darel also recently signed actress Mamie Gummer, daughter of Meryl Streep, as the new face of the company.
Darel will focus on developing its retail network in the U.K., Belgium, Spain, Italy and France, where it will double its store network to 80 locations within five years.
Future stores will be about 1,600 square feet, some 30 percent larger than those the company operates today.
The firm will also prioritize further developing business in fast-growing markets like Russia, South Korea and the United Arab Emirates. Expansion in the U.S., where the brand is sold in a handful of specialty stores and sales are not significant, is slated within five years.
Advent is a global buyout firm that has made more than 25 fashion and retail investments since it was founded in 1984, including Lululemon Athletica in the U.S. and Fat Face in the U.K. It is among a number of private equity players believed to be eyeing a stake in Roberto Cavalli.