Zac Posen — the designer known for his glamorous ballgowns and OTT runway presentations — at Brooks Brothers?

That's right. The “Project Runway” judge unveiled his first collection for the quintessentially preppy company on Saturday, and there were smiles all around.

“For me it wasn’t about a revolution, but an evolution,” Posen says about his approach to designing for such an iconic brand. “Brooks Brothers is the oldest American clothing brand, and I wanted to bring an elegance while representing true American style.”

That meant flirty lightweight tweed shifts, bold floral prints, easy culottes and silk shirtwaist dresses cut — like the Golden Age of Hollywood gowns he favors — on the bias. He topped off the looks off with colorful woven bucket hats. Adorable.