Italy's Valentino Fashion Group SpA has bought a 45% stake in US-based designer fashion label Proenza Schouler for $3.7m.

Valentino Fashion Group chief executive Stefano Sassi will become chairman of Proenza Schouler, and Shirley Cook will continue to serve its CEO.

Sassi said that the investment, along with Valentino Fashion Group's distribution network, will help support Proenza Schouler's international growth.