BY CHRISTINA BINKLEY

When real estate entrepreneur Aby Rosen wanted to restore his Gramercy Park Hotel to the forefront of New York's trend-setting scene, he invested in new paint and lighting, then turned to his wife, Samantha Boardman, for some fashion advice.

Which designer, he wondered, should create the wait staff's uniforms?

When Ms. Boardman's answer debuts on Monday at the hotel's Rose Bar and Gramercy Terrace, it will be one more detail the hotel can tick off in its drive to please an exacting, influential clientèle.

Instead of a design megastar, Ms. Boardman suggested Sophie Theallet, whose work is like a secret ...