Rachel Zoe spent sleepless nights over the Met Ball dress she designed for Karolina Kurkova.

Model Karolina stunned critics at the prestigious event in New York last week in a custom-made sequinned gold gown from the Rachel Zoe Collection, but the designer admits she was very nervous beforehand.

"I spent a lot of nights dreaming about what I wanted it to look like. Long sleeves, a very low back and a high neck were all musts for the dress, but the much-talked about headpiece was a last-minute addition. It happened literally the day before. 'What can I add to really take it to the next level?' So we made the turban-slash-head-wrap to give it that deco-glamour that [Elsa] Schiaparelli was so known for," said Rachel, who is a stylist to the stars.

Karolina, 28, walked the red carpet in the floor-length bodycon number at the Metropolitan Museum of Art's Costume Institute Gala with 40-year-old Rachel, who wore a white dress from Commes des Garcons.

Rachel was nervous about designing a custom-made piece for the prestigious New York City event: "Not in my lifetime did I think that it would be a reality," she admitted. "Honestly, I don't think I've recovered from it - it was hard work, a long process and an incredible process."

The Met Ball saw a number of other fashion-forward looks on celebrities like Florence Welch, Beyonce and Marc Jacobs - who wore a see-through lace shirt dress.