Proenza Schouler will continue to be based in New York, and the duo expects to be bolstering its design and sales team. They currently employ a staff of 13.

The designers also plan to open a sales office in Paris and a production office in Italy.

As for the duo's aspirations, they pointed to their upcoming eyewear launch, and a real push into handbags and shoes thereafter, followed by freestanding stores, and, one day, fragrance and even men's wear.

"As of now, we are primarily focused on the luxury end of women's," McCollough said.

For Permira, the deal is a small one. Founded in 1985, the company has raised funds worth approximately 22 billion euros, or $29.7 billion at current exchange, doing some 180 transactions in such diverse sectors as chemicals, technology, media, telecoms and industrial products and services. Investments in consumer products have ranged from British fashion retailer New Look and Italian tiles maker Marazzi Group to German lens and frames maker Rodenstock.

Last week, Permira said its takeover vehicle, Red & Black Lux Srl, struck a deal to buy 18.95 percent of VFG from Canova Partecipazioni SrL, a group of financial investors that includes VFG chairman Antonio Favrin. The Canova deal, pending antitrust approval, would lift Permira's total VFG stake to 60.2 percent.

Permira is looking to buy out minority shareholders and de­list VFG from the Milan Stock Exchange. It is offering all VFG shareholders 35 euros a share ($47.41 at current exchange), the same price Permira paid for the stakes owned by the Marzotto family and Canova.

The Red & Black tender offer could start as early as the last week of July and run through the first week of September. Red & Black will also launch a cascading bid for all outstanding shares in Hugo Boss AG. VFG owns 50.9 percent of Hugo Boss, which is listed on the Frankfurt Stock Exchange.

Asked if he would entertain more acquisitions, Sassi said it would depend on opportunities, but that anything that "can enhance Valentino Fashion Group's leadership is very welcome and will be entertained seriously."

The Proenza acquisition marks the establishment of "a sort of incubator of emerging, outstanding talent," Sassi said. "This is part of the activity of a group like ours. Permira as well agrees on this kind of strategy."