Christian Louboutin's design priority is sexiness.

The famed shoe designer insists he doesn't set out to create "painful" footwear but admits beauty and sexiness are his main considerations in his work.

"People say I am the king of painful shoes. I don't want to create painful shoes, but it is not my job to create something comfortable. I try to make high heels as comfortable as they can be, but my priority is design, beauty and sexiness. I'm not against them, but comfort is not my focus."

This year, Christian is celebrating 20 years in fashion and says his greatest career moment was creating the shoes worn at the finale of Yves Saint Laurent's final couture show - the only time the late designer ever collaborated with someone else: "I created those shoes just because I wanted to and I gave them to my dear friend Loulou de la Falaise. She wore them in front of Saint Laurent and he loved them and used them in his finale. When he was alive, he really was our biggest creative - it was such an honor."

While the designer's creations are a hit with a number of celebrities, the Duchess of Cambridge - who was known as Kate Middleton before she married Prince William - has not yet worn his shoes, but despite the royal being criticised for her safe fashion choices, Christian insists he wouldn't offer her advice.

"She has all the choice in the world. She's a very elegant young woman. I wouldn't give her any advice - she doesn't need it, let her choose for herself. She's a big girl now," he said.