Peter Sornen always makes sure the dresses he designs for Michelle Obama can be "altered".

The designer - who has created outfits for the fashionable First Lady on six separate occasions - is often given simple direction when he is asked to work on pieces for her, and always likes to have the option to change it at any moment.

He said: "I get an idea of colour, I get an idea of a size, and I make sure that it can be altered

"I have a more secure feeling knowing that it can be either let out or taken in. I have to have an idea of what she's feeling on wearing - if it's going to be an easy skirt, and not a fitted skirt.

"I'll send a swatch sometimes. Other times I was just given a direction, like, 'I want a true red,' or, 'It's got to be the most beautiful blue.' But they trusted me in a lot of things, which was great."

However, Peter always keeps quiet about his collaborations with the White House, not even telling his sales manager Ellen Carey.

He told New York Magazine: "I don't even tell Ellen until like, the day of, and I work with Ellen very closely. I'm very tight-lipped about it. I don't tell anyone."