WHEN IN ROME: Valentino creative directors Maria Grazia Chiuri and Pierpaolo Piccioli, who just scooped up the International Award from the CFDA, are on a major roll — and full of surprises.

Word has it the duo have designed a couture gown for former Gucci creative director Frida Giannini for her marriage to Patrizio di Marco, Gucci’s former chief executive officer. The religious ceremony is scheduled for Friday evening in Rome, and Chiuri and Piccioli are expected to be among the guests, sources said.

During the latter part of her Gucci tenure, Giannini was based in Rome, home of Valentino — and also Fendi, where the Italian designer started her fashion career.

Giannini and di Marco, who are partners in life and share a daughter, have been keeping a low profile since their abrupt departures from Gucci earlier this year.

It is understood the wedding celebrations spill over into Saturday, with sources speculating they could take place in Sabaudia, a beach resort about 60 miles from Rome, and a go-to vacation spot for Giannini.