"I love wearing a suit — with a white shirt, with nothing, with a cami," Rachel told us when asked about the sexy black number she designed for the model. "It’s just cool and it feels equal parts strong and sexy. It’s also an easy outfit and not too fussy. She can walk into any room, whether it’s the CFDA or any type of black tie event and it would be appropriate. That’s the other thing about a tux gowns. They’re literally appropriate at any cocktail or black tie party. Seasonless."